I’m not able to send e-mail with e-mail clients anymore and it is completely unclear as to why that may be.
When I run swaks to test the connection. It will throw
454 4.7.0 Temporary authentication failure: Connection lost to authentication server
*** No authentication type succeeded
Following postfix through journalctl when I execute swaks shows:
sudo journalctl -u postfix -f
postfix/submission/smtpd[18518]: Anonymous TLS connection established from localhost[::1]: TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256
postfix/submission/smtpd[18518]: warning: localhost[::1]: SASL LOGIN authentication failed: Connection lost to authentication server, sasl_username=(unavailable)
postfix/submission/smtpd[18518]: disconnect from localhost[::1] ehlo=2 starttls=1 auth=0/1 quit=1 commands=4/5
There appears suddenly a disconnect between Postfix and Dovecot when it comes to authentication. My credentials are correct as the webmail log-in works fine. The suggestion from my search is that it may be related to SASL, but the configuration suggestions to resolve my issue are what I already have in place.
Looking around on the Internet and spending several nights to get it to work I’m still stuck that using a client suddenly is not working anymore. I have used this virtual mail guide previously to configure my server for virtual mail. The configuration itself is all correct as the used configuration has been in place for several years now.