My settings are port 110. That was recommended in response to a previous question (here). I tried it with 995 and...

It said it was connecting to the server, then for 10 minutes...nothing. No messages were read (I had sent a test message after changing to 995.)

I changed it back to 110 and it works OK (as far as getting 

messages.)

Now when I get messages, I get "Sending of password for user xxxx@insight.rr.com did not succeed. Mail server mail.twc.com responded: invalid user name or password."

TROUBLESHOOTING INFORMATION

 Application Basics

   Name: Thunderbird
   Version: 52.5.2
   User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2
   Profile Folder: Open Folder

             (Local drive)
   Application Build ID: 20171221110448
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory
   Profiles: about:profiles

 Mail and News Accounts
   account1:
     INCOMING: account1, , (pop3) mail.twc.com:110, plain, passwordCleartext
     OUTGOING: , smtp-server.insight.rr.com:25, plain, passwordCleartext, true

   account2:
     INCOMING: account2, , (none) Local Folders, plain, passwordCleartext

   account4:
     INCOMING: account4, , (pop3) mail.twc.com:110, plain, passwordCleartext
     OUTGOING: , smtp-server.insight.rr.com:25, plain, passwordCleartext, true

 Crash Reports
   https://crash-stats.mozilla.com/report/index/bp-38b27962-ec29-49c9-8169-f38a10171014 (10/14/2017)
   https://crash-stats.mozilla.com/report/index/bp-e9490694-2a4e-47c0-a32a-f806d2160611 (6/11/2016)
   https://crash-stats.mozilla.com/report/index/bp-4720d4ef-95cf-45cf-8a89-bbde52150921 (9/21/2015)
   https://crash-stats.mozilla.com/report/index/bp-4daa1b71-495f-4d30-970a-dbf7e2150921 (9/21/2015)
   https://crash-stats.mozilla.com/report/index/bp-f54f9ce8-f0d8-42b3-bed1-8ee922140219 (2/19/2014)

 Extensions
   FiltaQuilla, 1.3.2, true, filtaquilla@mesquilla.com
   Lightning, 5.4.5.2, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}
   MoreFunctionsForAddressBook, 1.0b3, true, {3e17310d-82e8-4a43-bd2f-7c3055bfe589}
   Nostalgy, 0.2.35, true, nostalgy@alain.frisch
   Recover deleted messages, 0.4, true, {8380f54c-9b7a-4107-b703-9b938e30fb54}
   Remove Duplicate Messages, 0.1.14, true, {12345678-1234-1234-1234-123456789abc}

 Important Modified Preferences

   Name: Value

     accessibility.typeaheadfind.flashBar: 0
     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: 52.5.2

<snip snip font information>

     gfx.crash-guard.glcontext.appVersion: 45.6.0
     gfx.crash-guard.glcontext.deviceID: 0x0042
     gfx.crash-guard.glcontext.driverVersion: 8.15.10.2622
     gfx.crash-guard.glcontext.gfx.driver-init.direct3d11-angle: true
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle: true
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-d3d11: false
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-force-warp: false
     gfx.crash-guard.glcontext.gfx.driver-init.webgl-angle-try-d3d11: true
     gfx.crash-guard.status.glcontext: 2
     gfx.direct3d.last_used_feature_level_idx: 1
     mail.openMessageBehavior.version: 1
     mail.winsearch.enable: true
     mail.winsearch.firstRunDone: true
     mail.winsearch.global_reindex_time: 1314206108
     mailnews.database.global.datastore.id: 5fb804db-1574-4f13-9580-ab68c20fc87
     mailnews.database.global.views.conversation.columns: {"threadCol":{"visible":true,"ordinal":"1"},"flaggedCol":{"visible":true,"ordinal":"3"},"attachmentCol":{"visible":false…
     media.gmp.storage.version.observed: 1
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1516938020
     places.history.expiration.transient_current_max_pages: 53853
     plugin.disable_full_page_plugin_for_types: application/pdf
     plugin.importedState: true
     <snip snip printer information>
     security.sandbox.content.tempDirSuffix: {5cde54d8-8f43-4cdd-9421-783fde97787f}

 Graphics

     GPU #1
     Description: Intel(R) HD Graphics
     Vendor ID: 0x8086
     Device ID: 0x0042
     RAM: Unknown
     Drivers: igdumd64 igd10umd64 igdumdx32 igd10umd32
     Driver Version: 8.15.10.2622
     Driver Date: 1-10-2012

     Features
     Direct2D: false
     DirectWrite: true (6.2.9200.22164)
     WebGL Renderer: Google Inc. -- ANGLE (Intel(R) HD Graphics Direct3D9Ex vs_3_0 ps_3_0) -- OpenGL ES 2.0 (ANGLE 2.1.0.2a250c8a0e15)

     AzureCanvasBackend: skia
     AzureCanvasAccelerated: 0
     AzureFallbackCanvasBackend: cairo
     AzureContentBackend: skia

 JavaScript

 Incremental GC: 1

 Accessibility

   Activated: 0
   Prevent Accessibility: 0

 Library Versions

     Expected minimum version
     Version in use

     NSPR
     4.13.1
     4.13.1

     NSS
     3.28.6
     3.28.6

     NSS Util
     3.28.6
     3.28.6

     NSS SSL
     3.28.6
     3.28.6

     NSS S/MIME
     3.28.6
     3.28.6

They now are saying that they do not support TB! Furthermore, they know that no other cable provider supports TB or any 3rd party email client. They say I need to re-configure TB.

So, please walk m through the steps I need to take to re-configure TB.

Thanks. Phil Richcreek

My list of saved logon does not show the twc.mail.com. How do I add it to that list? Thanks. Phil

I'd delete all of those obsolete logins now.

You don't add logins to that box. Thunderbird does that.

When you are prompted for a password, the dialogue has a checkbox which tells Thunderbird to remember your password. Have you ticked this?

"When you are prompted for a password,"

The instructions said to change "server settings" in TB, including smtp. I decided to change the smtp first, because it would be simpler. However, I was never promped for a password, even after removing all the smtp.insight entries in saved passwords.

I sent a test message to myself and to another account, It was received on the other account and also in TWC Webmail. I can't say whether it was received in philrichcreek, because I'm unable to view any new messages there! It seems clear that TWC is keeping track of logins "on its own", independent of TB configuration.

I'll give the POP server settings a try. Thanks. Phil Richcreek.

Here's an update on the status of this matter.

• I've changed the pop-server back to 110.
• I'm able to go into philxxx@insight.rr.com with no

 prompt or error message. 

• Get Messages now works. That is, I see new messages.
• Write (Send a message) now works. No prompt or error

  message.

In other words, this look great. However...

Here's what's puzzling.

A second account cellxxx@insight.rr.com can send. No prompt or error message (that's normal.) However, when I do Get Message, I get "Error with account cellxxx@insight.rr.com" "Sending of password for cellxxx did not succeed. Mail server mail.twc.com responded: invalid user name or password."

It makes me wonder if TWC is restricting the account to one email address?

Changing password for cellist from 4jn to 3jn did not change anything. Still getting login failed message.

I feel that we've done everything TWC asked us to do--reconfigure TB settings. I will report back to them that the changes corrected the problem for only one email address. I will ask them whether my "limit to 1 email address per account" theory explains why reconfigure TB didn't fix the other account.

Thanks. Phil.

TWC support says that the problem is with TB. I have two TB account on this computer. Philxxx@insight.rr.com and Cellxxx@insight.rr.com. Philxxx is working fine with TWC. Cellxxx is not working--meaning that Cellxxx cannot see new emails. All new messages can be seen in TWC Webmail. And all the TB settings are the same on the two account (except passwords, of course.) Their conclusion is that since TWC Webmail can see all the messages, it must be a TB problem. Very strange logic.

The last agent I talked to said I just need to be patient. CellXXX will eventually work. He can't say when it will work but I just need to be patient.

For the record, the ticket number for all this is 7367241.

Thanks to Zenos and sfhowes for their help. Phil.