Please provide more information. In my two decades of using Thunderbird, links have always linked as anticipated.

The only links that are deliberately non-clickable are ones entered in the message composition window. Otherwise, links that are underlined and with blue text should be clickable, as long as TB is properly set to open links in the system default browser. Links that are not coloured or underlined sometimes appear and are not clickable, but that is generally because the sending mail client fails to correctly format links. The Mail app in W10/11 is one example, and it also happens with some mobile mail apps.

Try sending a plain text message with a link to yourself with TB. If the received message isn't clickable, consult the diagnostic steps here:

https://support.mozilla.org/en-US/kb/hyperlinks-in-messages-not-working

The only links that are deliberately non-clickable are ones entered in the message composition window.

I agree that this is how it should work, but the forum moderator here is claiming that some links are indeed deliberately non-clickable, and it can be a major nuisance - for example:

On Mac OS, Zoom meeting links are actionable in Microsoft Outlook and Mac Mail, but they do nothing in Thunderbird — the URL’s look & work like plain text. Now perhaps this depends on how and where the message was composed: if I forward the meeting invitation to myself from Thunderbird, links in the received message will work. But the leading mail applications handle these links correctly without any manual intervention. In my opinion, Thunderbird should conform to the de-facto standard that was established by Apple & Microsoft here:

While I do not use or recommend Zoom, joining meetings by mail invite should be supported for the sake of usability — and this is already supported in outgoing messages. The primary benefit of Thunderbird is cross-platform compatibility …but in this particular case, we are lagging instead of leading.

I tried to post examples here of working and broken message source, but this forum does not permit me to quote the HTML -- instead it tries to interpret that. So both of these are exactly backwards: the forum attempts to interpret text where it should not, and the app neglects to interpret text where it should.

Please provide more information. In my two decades of using Thunderbird, links have always linked as anticipated.

This bug was reported in 2003 and there are many duplicates under different titles. Here is the latest. https://bugzilla.mozilla.org/show_bug.cgi?id=1897855