Hi StrorminNorman This might be a setting in Thunderbird, or indicate the link is fraudulent, or that the link is incomplete, or that you don't have the program it needs in order to run. I assume you were expecting this confirmation message, and it is from a legitimate source. This page describes how to check Thunderbird settings can open a Web link https://support.mozilla.org/en-US/kb/hyperlinks-in-messages-not-working#w_check-that-no-application-is-specified-for-the-http-content-type If it is a web link, it should open a browser. You could try copying the link, opening your preferred browser, and pasting the link in the address bar. That may help identify if the link is incomplete or broken. You didn't say what kind of device and operating system you are using. There should be a way to tell your operating system what program to open for this kind of link or file (i.e. which browser to use when opening a link). Try changing the default browser in those settings, and then try the Thunderbird link again. You can later change the default browser back again - and sometimes just making the operating system change the default, and then setting it back to normal, is enough to fix the problem. I hope some of this helps, Agnes