In the image you posted there seems to be several things incorrect. This seems unusual as Thunderbird knows the server settings for gmail imap.

• Incoming server name: imap.gmail.com
• Port: 993
• Connection Security: SSL/TLS
• Authentication Method: OAuth2
• User name : Full gmail email address.

• Outgoing SMTP server name: smtp.gmail.com
• Port: 465
• Connection Security: SSL/TLS
• Authentication Method: OAuth2
• User name : Full gmail email address.

Upon clicking on 'done', gmail will auto redirect you to a browser login to check that you really are you. Then gmail will create an AOuth token which will get stored in Thunderbird in the same place as passwords. From then onwards Thunderbird will connect to gmail servers using the token instead of the password.

When you initially start to create the account. In Thunderbird

Menu icon (3 lines) > New > Existing mail account Enter name Enter full gmail email address Enter Password - same one you use to access webmail account. Select checkbox to remember password click on 'Continue' Thunderbird should locate the correct settings and usually choose imap be default. You could then click on 'Manage Config' to see the window you posted. Check all settings are correct including the user name being full email address.

Thanks for your prompt reply. I've worked through these steps countles times and always have to manually choose the ports as Thunderbird defaults to Auto, and Autodetect for the SSL: and authentication. It makes no difference, the 'done' button is greyed out with the same 'failed to find the settings' message. I've checked my p/w with gmail and that's correct. Geoff

But most the information in that image you posted was wrong, so it would fail anyway. In the Manual Config window....

the incoming and outgoing server names were wrong. you do not mention whether you corrected it.

the username for incoming and outgoing was obviously not a full gmail email address, so that would fail as well. In image I've slightly edited this for obvious reasons, but it should be full email address. you do not mention whether you corrected it.

Port and connection Security should be as per image below.

As it is an imap mail account, it should be set up to use 'OAuth2' and that was not selected either.

Please try again and make sure you edit everything so it is correct. If one thing is wrong then it will fail.

See the info in the image attached. Make sure you set up the same. Then click on 'Retest' which is not disabled to reconnect with server. Post image of what you test using.

'OAuth2' is not an option (see attached pic). everything else is set correctly as far as I'm aware. When I click 're-test' I get the same message.

Geoff

PS. I'm now going to be away from the computer until tommorrow afternoon. Many thanks.

When creating an account Thunderbird reaches out to the internet to get the settings.

For example the gmail settings are located here https://autoconfig.thunderbird.net/v1.1/gmail.com

That Thunderbird is unable to get those settings indicates that Thunderbird is being denied access to the internet. This is usually caused by firewall products, internet security suites being the most common.

One thing is certain. If Thunderbird can not connect to get the settings from it's own database server, it will not works to get mail either. Regardless of the settings used.

Hi. Yes, I'm sure the problem is on my Mac. The reason I was trying Thunderbird was that my Mail app was failing to send emails, though it can receive them. I've tried using Outlook and that has the same problem, so I'm looking now to see what, on my Mac, has suddenly changed. Thanks for your time. regards Geoff

Figure anything out Geoff?

Hi Matt. Afraid not. I've just tried setting up my little-used Yahoo account with Mail, but once again I get the message:

'Mail was unable to connect to server smtp.mail.yahoo.com using the default ports. Verify that this server supports SSL and that your account settings are correct.'

This is a similar message to the Gmail ones and I know my settings were correct (They have been unchanged since I purchased this Mac a couple of years ago). Receiving mail is no problem and I can send using web mail, but that's very inconvenient. I have no security software and don't use a firewall, but something is preventing me accessing these servers. Any thoughts greatly appreciated. Years ago I used to be ahead of the game where Macs and the internet were concerned, now it's all passing me by! Regards Geoff

How exactly does your machine connect to the internet? Most routers for instance have a firewall.

Did you check the apple settings? https://support.apple.com/en-au/HT201642

Do you use a VPN? They are becoming quite popular in certain markets and are VERY mail unfriendly, usually causing it to fail completely. (Nord appears here with some regularity because they claim to support mail but the American/ Canadian ISPs often don't support the access via a VPN. They use IP address to determine if they will accept a connection. This is not the case with yahoo et al, but they do geo locate based on IP and may block what they see as out of character locations.

try using telnet to determine if port blocking is the issue. https://www.siteground.com/kb/check-port-blocked-isp/

I have had EE fibre broadband with no firewall set up for the past 18 months. I know nothing about VPN. Just checked the Apple settings and they are OK. Looked at siteground and followed their instructions (though I'm not sure what I was supposed to type in). Received : bash: telnetgmail.com: command not found

What has just occurred to me is that theses problems began around the time I purchased a new iPhone and my broadband contract was renewed, so I'm now wondering if there was a setup issue. I'll contact EE and if they can resolve the problem, I'll let you know.

regards Geoff

Not much used to the command line hey. Type

telnet smtp.gmail.com 465

still no good. typed with and without the space before 465. Geoff

I do not see you typing telnet which is the actual program you are executing. The rest are command line parameters that cause it to reach out to the gmail server and attempt to connect to it on port 465.

Still no results. See attached screenshot. Geoff

As you might have guessed macos is not something I use.

Apparently apple decided to replace telnet in High Sierra with something called nc So apparently the command is

nc -vz smtp.gmail.com 465

What hub/router are you using? It is likely to have some sort of firewall to block ports etc. Is it set up to allow the ports you need to access smtp port 465?

Hi Matt. The new command worked, but not sure where that leaves me. See atached shot

Hi Toad-Hall. Just spent some time with my internet provider (EE) who has tried various options. He confirms there is no firewall set up.

Geoff

Just triued to send an email using the apple Mail app on my iPhone. That also failed with the message the connection to the outgoing server smtp.gmail.com failed' Geoff

The last image you posted showing the attempt to set up account, now shows correct port, connection security and username, But it still does not have the correct server names for incoming and outgoing. incoming server name is not .gmail.com, it is imap.gmail.com outgoing server name is not .gmail.com, it is smtp.gmail.com

As you may/maynot be connecting to gmail using AOuth2....logon to gmail webmail account via a browser and make sure you have setup to use 'less secure apps' option.