IMAP troubleshooting

[klaus-dieter.fietze at bluewin.ch]

I wonder if someone can help me troubleshooting my kmail IMAP account. Actually, my account on imaps.bluewin.ch was nicely running for years until something happened a few weeks ago. Since then, I am desperately trying to reconnect to my mail account in vain. My parameters and credentials cannot be wrong since they work with Thunderbird. I suspect Akonadi to hide old settings deep down in one of its databases. I am sure I could solve the issue by installing a fresh Tumbleweed system but this would not prevent other users from running into the same problem.
Let me know what I can do – I have time. It would be my pleasure if I could contribute to a solution and thus give something back to the community of open source.
Thank you in advance !
Klaus
Operating System: openSUSE Tumbleweed 20210401
KDE Plasma Version: 5.21.3
KDE Frameworks Version: 5.80.0
Qt Version: 5.15.2
Kernel Version: 5.11.6-1-default
OS Type: 64-bit
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-7700T CPU @ 2.90GHz
Memory: 7.6 GiB of RAM
Graphics Processor: Mesa DRI Intel® HD Graphics 630
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