I've used Thunderbird for many years and occasionally a message I've sent takes ages being saved, then finally it isn't. This has become more frequent recently together with having to re-enter my email password. I use Ubuntu (22.04.4 LTS) so I don't use anti-virus software and I don't use other email clients (only Thunderbird 115.10.1 64 bit).

I sometimes briefly lose my internet connection, though seemingly not when the email malfunctions, so could my old BT hub be the source of the problems? In the absence of any other solution maybe it's time to get a Chromebook and see if that's any better with Thunderbird. Firefox also now freezes a couple of times a week (and not being an IT wizard I hate not knowing what incantations to type into the terminal when anything goes wrong.)