warning: SASL authentication failure: cannot connect to saslauthd server: No such file or directory

Well,

digged the web and nearly drove crazy. By entering

ls -la /var/spool/postfix/var/run/saslauthd

it had shown, that the directory is empty.

After literally hours of search i came across this. Stop the instance of saslauthd and restart it.

/etc/init.d/saslauthd stop-instance saslauthd /etc/init.d/saslauthd start-instance saslauthd

this fixed it.

Just in case.

Best