If your messages are being dumped into the recipient's Spam folder then no, you wouldn't get any warning.

If your SMTP server isn't complaining then we have to assume it has done its job. It found somewhere to send your messages.

If you're not getting messages from remote servers reporting inaccessible mailboxes then they have done their job too.

Which leaves it looking like your messages have been sent but swallowed by anti-Spam systems.

Does it work if you send messages to/from yourself, ideally between two different accounts?

Is any of the lost material lurking in your Outbox, under Local Folders?

Thank you for you help. I have sent messages to myself, my wife, my daughter and none of them arrive nor can they be found in junk or spam folders. When I go on line and send directly from my email account there is no problem. About the same time this problem started I began receiving dozens of notices from MAILER-DAEMON@mail404.opentransfer.com and similar sources saying mail could not be delivered. These referred to mail sent to addresses I have never used and are not in my address book. It seems to be some kind system to spread viruses. I have not opened any of the attachments to these and delete them as they arrive.

Please add the troubleshooting information to your post To find the Troubleshooting information:

• Open Help (or click on three-line-icon and select Help)
• Choose Troubleshooting Information
• Use the button Copy to clipboard to select all. Do not check box "Include account names"!
• Paste this in your post.

Here is the trouble shooting information.

 Application Basics

   Name: Thunderbird
   Version: 52.1.1
   User Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1
   Profile Folder: Open Folder

             (Local drive)
   Application Build ID: 20170509142926
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory
   Profiles: about:profiles

 Mail and News Accounts
   account1:
     INCOMING: account1, , (none) Local Folders, plain, passwordCleartext

   account2:
     INCOMING: account2, , (pop3) mail.jadeplc.org:110, plain, passwordCleartext
     OUTGOING: , mail.jadeplc.org:587, plain, passwordCleartext, true

 Crash Reports

 Extensions
   Lightning, 5.4.1.1, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}

 Important Modified Preferences

   Name: Value

     browser.cache.disk.capacity: 358400
     browser.cache.disk.filesystem_reported: 1
     browser.cache.disk.smart_size_cached_value: 358400
     browser.cache.disk.smart_size.first_run: false
     browser.cache.disk.smart_size.use_old_max: false
     dom.apps.reset-permissions: true
     extensions.lastAppVersion: 52.1.1
     font.internaluseonly.changed: false
     font.name.monospace.el: Consolas
     font.name.monospace.tr: Consolas
     font.name.monospace.x-baltic: Consolas
     font.name.monospace.x-central-euro: Consolas
     font.name.monospace.x-cyrillic: Consolas
     font.name.monospace.x-unicode: Consolas
     font.name.monospace.x-western: Consolas
     font.name.sans-serif.el: Calibri
     font.name.sans-serif.tr: Calibri
     font.name.sans-serif.x-baltic: Calibri
     font.name.sans-serif.x-central-euro: Calibri
     font.name.sans-serif.x-cyrillic: Calibri
     font.name.sans-serif.x-unicode: Calibri
     font.name.sans-serif.x-western: Times New Roman
     font.name.serif.el: Cambria
     font.name.serif.tr: Cambria
     font.name.serif.x-baltic: Cambria
     font.name.serif.x-central-euro: Cambria
     font.name.serif.x-cyrillic: Cambria
     font.name.serif.x-unicode: Cambria
     font.name.serif.x-western: Cambria
     font.size.fixed.el: 14
     font.size.fixed.tr: 14
     font.size.fixed.x-baltic: 14
     font.size.fixed.x-central-euro: 14
     font.size.fixed.x-cyrillic: 14
     font.size.fixed.x-unicode: 14
     font.size.fixed.x-western: 14
     font.size.variable.el: 17
     font.size.variable.tr: 17
     font.size.variable.x-baltic: 17
     font.size.variable.x-central-euro: 17
     font.size.variable.x-cyrillic: 17
     font.size.variable.x-unicode: 17
     font.size.variable.x-western: 17
     gfx.direct3d.last_used_feature_level_idx: 0
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: 376b4cb5-b540-4d8c-9804-2b5b0f098e2
     mailnews.database.global.views.conversation.columns: {"threadCol":{"visible":true,"ordinal":"3"},"flaggedCol":{"visible":true,"ordinal":"7"},"attachmentCol":{"visible":false…
     media.gmp.storage.version.observed: 1
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1496278125
     places.history.expiration.transient_current_max_pages: 122334
     plugin.importedState: true
     plugin.state.npgoogletalk: 0
     plugin.state.npo1d: 0
     plugin.state.npwinext: 0
     plugins.update.notifyUser: true
     print.print_printer: Canon MP250 series Printer OFFICE
     print.printer_Canon_iP4200.print_bgcolor: false
     print.printer_Canon_iP4200.print_bgimages: false
     print.printer_Canon_iP4200.print_command:
     print.printer_Canon_iP4200.print_downloadfonts: true
     print.printer_Canon_iP4200.print_evenpages: true
     print.printer_Canon_iP4200.print_footercenter:
     print.printer_Canon_iP4200.print_footerleft: &PT
     print.printer_Canon_iP4200.print_footerright: &D
     print.printer_Canon_iP4200.print_headercenter:
     print.printer_Canon_iP4200.print_headerleft: &T
     print.printer_Canon_iP4200.print_headerright: &U
     print.printer_Canon_iP4200.print_in_color: true
     print.printer_Canon_iP4200.print_margin_bottom: 0.5
     print.printer_Canon_iP4200.print_margin_left: 0.5
     print.printer_Canon_iP4200.print_margin_right: 0.5
     print.printer_Canon_iP4200.print_margin_top: 0.5
     print.printer_Canon_iP4200.print_oddpages: true
     print.printer_Canon_iP4200.print_orientation: 0
     print.printer_Canon_iP4200.print_pagedelay: 500
     print.printer_Canon_iP4200.print_paper_data: 9
     print.printer_Canon_iP4200.print_paper_height: 11.00
     print.printer_Canon_iP4200.print_paper_size: 1718558835
     print.printer_Canon_iP4200.print_paper_size_type: 0
     print.printer_Canon_iP4200.print_paper_size_unit: 1
     print.printer_Canon_iP4200.print_paper_width: 8.50
     print.printer_Canon_iP4200.print_reversed: false
     print.printer_Canon_iP4200.print_scaling: 1.00
     print.printer_Canon_iP4200.print_shrink_to_fit: true
     print.printer_Canon_iP4200.print_to_file: false
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_bgcolor: false
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_bgimages: false
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_colorspace:
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_command:
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_downloadfonts: false
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_duplex: -437918235
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_edge_bottom: 0
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_edge_left: 0
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_edge_right: 0
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_edge_top: 0
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_evenpages: true
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_footercenter:
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_footerleft: &PT
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_footerright: &D
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_headercenter:
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_headerleft: &T
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_headerright: &U
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_in_color: true
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_margin_bottom: 0.5
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_margin_left: 0.5
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_margin_right: 0.5
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_margin_top: 0.5
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_oddpages: true
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_orientation: 0
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_page_delay: 50
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_paper_data: 1
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_paper_height: 11.00
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_paper_name:
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_paper_size_type: 0
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_paper_size_unit: 0
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_paper_width: 8.50
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_plex_name:
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_resolution: -437918235
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_resolution_name:
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_reversed: false
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_scaling: 1.00
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_shrink_to_fit: true
     print.printer_Canon_MG2900_series_Printer_(Copy_1).print_to_file: false

Among the many notices of email rejections received today I got this which maybe just more of the same but is different from the others. Please note that these rejections from from messages I have not sent and the addresses are not in the address book.

McAfee® NOTIFICATION ALERT

Email Gateway Virtual Appliance triggered Information:

Scanner(s): Anti Spam Context(s): unknown Detection(s): NAI_BAD_URI=7.5, TS_MSG_REP_40=3, MAL_EJDTP=1, URI_RND_NM=0.4, RCVD_ESMPT_UC=0.3, EDT_SA_AU_PASS=0, EDT_SA_DN_PASS=0, EDT_SA_FD_PASS=0, EDT_SA_RB_PASS=0, EDT_SA_SI_NONE=0, EDT_SA_SP_NONE=0, EDT_SA_TS_PASS=0, RV6039=0 Source IP Address: 98.130.1.134 Source Host Name: 98.130.1.134 Sender: <alan@jadeplc.org> Recipients: <bestbart@dstsystems.com> Destination IP Address: Destination Host Name: Message ID: 2341_1a55_9b94bbe5_b90f_4724_8d50_1d9d648b66b9 Email Gateway Virtual Appliance: IC-HE3MGW1.dstcorp.net Email Gateway Virtual Appliance IP Address: 10.243.70.51 Protocol: smtp UTC Time: 2017-06-04_07:43:24_GMT_(+0000) Local Time: 2017-06-04_02:43:24_CDT_(-0500)

See your system administrator for further information.

This is a guess amde on the strength of the available facts.

You are caught up in the backscatter from the work of a spammer See https://en.wikipedia.org/wiki/Backscatter_(email)

A possible ramification of this is your sending address could now be flagged as a spammer on some mail servers. One US ISP marks an address as a spammer if three of their million or so customers click the spam button in their web mail for instance.

However to move on. A check with dnsstuff on the domain flags the mail server as an open relay. This is a very serious breach as it allows the spammers to use the mail server for jadeplc.org to send their spam without any control. A sure way for other mail servers to blacklist you as a spammer. open relays have been getting less for 20 years or more. Those that exist now are usually considered as misconfigured by the server admin.

See http://www.dnsstuff.com/tools#dnsReport|type=domain&&value=jadeplc.org

If you are the domain owner, I siggest you contact the web hosting company See http://www.ixwebhosting.com/

They can assist in setting the mail up correctly so it is not used for spam and perhaps assist you in getting your mail delivered following the event.

So as Zenos said, there is not an issue with the sending. It is in the receiving that the trouble lies and that can only be addressed by the web host, as that is where the problem originated.

Perhaps I might point out that their mail server mail.ixwebhosting.com/ is registered as the mail exchanger. SO my guess is their web mail uses that and they only use the mail server registered for the domain to send mail from mail clients.

Thank you Matt for devoting time to this. When I log in to my email server at IXwebhosting through webmail.opentransfer.com, I have no problem sending mail from there and it is delivered without problem. It is only when I use Thunderbird that I have this problem. Since thunderbird is only sending mail through the same email account it would seem there must be something between thunderbird and the email server. I will contact ixwebhosting to see what they can do but it seems more likely that something in thunderbird has been corrupted or changed.

Sending messages at the providers webmail site does not use a SMTP server that an email client like Thunderbird does. Trying to compare the two is irrelevant. SMTP servers blacklist spammers and webmail pages do not. You need to find out the status of your address or IP address.

Edit: Not saying you are the spammer but your address or IP might be tagged as such.

alzhuhai said

I will contact ixwebhosting to see what they can do but it seems more likely that something in thunderbird has been corrupted or changed.

Make sure to ask about the open relay... that is really bad karma to the point you could be blacklisted by other mail servers simply for having an open relay.

IXwebhosting regarding the open relay situation says: Stas Beloshitskiy While address for MX record (in fact it is IronPort) may be considered an open relay, we don't allow sending emails without authentication.

On my account settings it says: password transmitted insecurely Connection security: none Should I change this to SSL/TSL?

Zeno summed it up way back at the beginning. https://support.mozilla.org/en-US/questions/1162721#answer-974603

There is no pont looking at Thunderbird. It is working correctly.The problem with delivery is firther from the source.

If your connection settings were wrong you would not connect. IF the SMTP server did not like the mail you were sending it would give an error that you would see before the mail disappeared from the screen in front of you.

Ipso fact there is a problem further up the line. My guess is your provider have managed to get themselves on a blacklist for sending mail. But that is just a guess.