Guys, it works! With Thunderbird as well as with my Smartphone client.
You have no imagination how happy I am. Thanks a lot!
What I did …
- I cleaned all Dovecot .conf files for duplicated or conflicting settings
- I applied the suggested changes by Buffalo
I also applied the addition as suggested by Jürgen. But was neither necessary nor did harm, so I commented it out for now.
Don’t forget to check validity with ‘dovecot -n’ and restart Dovecot.
Thanks a lot guys,
you made not only my day but my quarter
Chris