Mailbox connection fails: Connection closed (No commands sent) Help please

[Alexander Dalloz]

Am 07.12.2021 um 22:45 schrieb postfix at aecperformance.com:
> My VPS IP is: 194.163.45.150

Use a not expired certificate.

$ openssl s_client -connect 194.163.45.150:993
CONNECTED(00000003)
depth=3 O = Digital Signature Trust Co., CN = DST Root CA X3
verify error:num=10:certificate has expired
notAfter=Sep 30 14:01:15 2021 GMT
verify return:0

Alexander