E-mail not sent, test e-mail returns an error

[Mornagest]

/var/log/exim4/mainlog:

[...]2020-12-10 08:08:49 SMTP protocol error in "AUTH LOGIN" H=(User) [103.253.42.54] AUTH command used when not advertised
2020-12-10 08:10:57 no host name found for IP address 141.98.10.143
2020-12-10 08:10:57 SMTP protocol error in "AUTH LOGIN" H=(User) [141.98.10.143] AUTH command used when not advertised
2020-12-10 08:15:25 SMTP protocol error in "AUTH LOGIN" H=mone183.secundiarourous.com (User) [141.98.10.183] AUTH command used when not advertised
2020-12-10 08:20:20 no host name found for IP address 141.98.10.136
2020-12-10 08:20:20 SMTP protocol error in "AUTH LOGIN" H=(User) [141.98.10.136] AUTH command used when not advertised
2020-12-10 08:20:45 SMTP protocol error in "AUTH LOGIN" H=(User) [45.125.65.105] AUTH command used when not advertised
2020-12-10 08:23:30 Start queue run: pid=22946
2020-12-10 08:23:30 End queue run: pid=22946
2020-12-10 08:40:29 no host name found for IP address 141.98.10.192
2020-12-10 08:40:29 SMTP protocol error in "AUTH LOGIN" H=(User) [141.98.10.192] AUTH command used when not advertised
2020-12-10 08:42:11 SMTP protocol error in "AUTH LOGIN" H=(User) [45.125.65.39] AUTH command used when not advertised
2020-12-10 08:42:44 SMTP protocol error in "AUTH LOGIN" H=(User) [45.125.65.105] AUTH command used when not advertised
2020-12-10 08:45:05 SMTP protocol error in "AUTH LOGIN" H=(User) [103.253.42.54] AUTH command used when not advertised

Nothing about that test mail... I send it at 8:43.

/var/log/exim4/rejectlog is empty.


Here could the hell be the error vBulletin tells me about writen down?

Thank you for your help, Snakes1100!