Thank you very much for looking at my problem.
Dovecot logs:
dovecot-mailcow_1 | Jul 23 15:27:43 370ff00ce296 dovecot: lmtp(195554): Connect from 172.22.1.1
dovecot-mailcow_1 | Jul 23 15:27:43 370ff00ce296 dovecot: lmtp(195554): Disconnect from 172.22.1.1: Client has quit the connection (state=READY)
dovecot-mailcow_1 | Jul 23 15:27:43 370ff00ce296 dovecot: imap-login: Aborted login (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250, TLS, TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
dovecot-mailcow_1 | Jul 23 15:27:43 370ff00ce296 dovecot: imap-login: Aborted login (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:27:43 370ff00ce296 dovecot: managesieve-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:28:54 370ff00ce296 dovecot: lmtp(195681): Connect from 172.22.1.1
dovecot-mailcow_1 | Jul 23 15:28:54 370ff00ce296 dovecot: lmtp(195681): Disconnect from 172.22.1.1: Client has quit the connection (state=READY)
dovecot-mailcow_1 | Jul 23 15:28:54 370ff00ce296 dovecot: imap-login: Aborted login (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250, TLS, TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
dovecot-mailcow_1 | Jul 23 15:28:54 370ff00ce296 dovecot: imap-login: Aborted login (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:28:54 370ff00ce296 dovecot: managesieve-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:28:55 370ff00ce296 dovecot: imap-login: Disconnected (auth failed, 1 attempts in 0 secs): user=<mwehr@fwsmail.de>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:28:55 370ff00ce296 dovecot: imap-login: Disconnected (auth failed, 1 attempts in 0 secs): user=<mwehr@fwsmail.de>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:28:55 370ff00ce296 dovecot: imap-login: Disconnected (auth failed, 1 attempts in 0 secs): user=<mwehr@fwsmail.de>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:28:55 370ff00ce296 dovecot: imap-login: Disconnected (auth failed, 1 attempts in 0 secs): user=<mwehr@fwsmail.de>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:28:55 370ff00ce296 dovecot: imap-login: Disconnected (auth failed, 1 attempts in 0 secs): user=<mwehr@fwsmail.de>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:28:55 370ff00ce296 dovecot: imap-login: Disconnected (auth failed, 1 attempts in 0 secs): user=<mwehr@fwsmail.de>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:30:13 370ff00ce296 dovecot: lmtp(195744): Connect from 172.22.1.1
dovecot-mailcow_1 | Jul 23 15:30:13 370ff00ce296 dovecot: lmtp(195744): Disconnect from 172.22.1.1: Client has quit the connection (state=READY)
dovecot-mailcow_1 | Jul 23 15:30:13 370ff00ce296 dovecot: imap-login: Aborted login (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250, TLS, TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
dovecot-mailcow_1 | Jul 23 15:30:13 370ff00ce296 dovecot: imap-login: Aborted login (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:30:13 370ff00ce296 dovecot: managesieve-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250
dovecot-mailcow_1 | Jul 23 15:30:35 370ff00ce296 dovecot: lmtp(195744): Connect from 172.22.1.1
dovecot-mailcow_1 | Jul 23 15:30:35 370ff00ce296 dovecot: lmtp(195744): Disconnect from 172.22.1.1: Client has quit the connection (state=READY)
dovecot-mailcow_1 | Jul 23 15:30:36 370ff00ce296 dovecot: imap-login: Aborted login (no auth attempts in 0 secs): user=<>, rip=172.22.1.1, lip=172.22.1.250, TLS, TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
SOGO logs:
sogo-mailcow_1 | Jul 23 15:28:42 369057c07bd2 sogod [67]: 37.4.250.60 "GET /SOGo/ HTTP/1.0" 200 9857/0 0.021 34323 71% 0 - 13
sogo-mailcow_1 | Jul 23 15:28:50 369057c07bd2 sogod [67]: SOGoRootPage successful login from '37.4.250.60' for user 'mwehr@fwsmail.de' - expire = -1 grace = -1
sogo-mailcow_1 | Jul 23 15:28:50 369057c07bd2 sogod [67]: 37.4.250.60 "POST /SOGo/connect HTTP/1.0" 200 49/92 0.283 - - 0 - 14
sogo-mailcow_1 | Jul 23 15:28:51 369057c07bd2 sogod [67]: 37.4.250.60 "GET /SOGo/mwehr%40fwsmail.de HTTP/1.0" 302 0/0 0.004 - - 0 - 14
sogo-mailcow_1 | Jul 23 15:28:51 369057c07bd2 sogod [67]: 37.4.250.60 "GET /SOGo/mwehr%40fwsmail.de/view HTTP/1.0" 302 0/0 0.007 - - 0 - 14
sogo-mailcow_1 | Jul 23 15:28:51 369057c07bd2 sogod [67]: 37.4.250.60 "GET /SOGo/so/mwehr@fwsmail.de/Mail HTTP/1.0" 302 0/0 0.005 - - 0 - 14
sogo-mailcow_1 | Jul 23 15:28:51 369057c07bd2 sogod [67]: 37.4.250.60 "GET /SOGo/so/mwehr@fwsmail.de/Mail/view HTTP/1.0" 200 22090/0 0.032 85913 74% 2M - 14
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: 37.4.250.60 "GET /SOGo/so/mwehr@fwsmail.de/Calendar/alarmslist?browserTime=1627046935 HTTP/1.0" 200 63/0 0.011 - - 0 - 14
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: [ERROR] <0x0x56052f7f7a10[NGImap4ConnectionManager]> IMAP4 login failed:
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 host=172.22.1.250, user=mwehr@fwsmail.de, pwd=yes
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 url=imap://mwehr%40fwsmail.de@172.22.1.250/?tls=NO&tlsVerifyMode=none
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base=(null)
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base-class=(null))
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 = <0x0x56052fd268e0[NGImap4Client]: login=mwehr@fwsmail.de(pwd) socket=<NGActiveSocket[0x0x56052fde5a80]: mode=rw address=<0x0x56052fde5af0[NGInternetSocketAddress]: host=369057c07bd2 port=38888> connectedTo=<0x0x56052fd29ff0[NGInternetSocketAddress]: host=172.22.1.250 port=143>>>
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: <0x56052fccaa20[SOGoMailAccount]:0> renewing imap4 password
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: [ERROR] <0x0x56052f7f7a10[NGImap4ConnectionManager]> IMAP4 login failed:
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 host=172.22.1.250, user=mwehr@fwsmail.de, pwd=yes
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 url=imap://mwehr%40fwsmail.de@172.22.1.250/?tls=NO&tlsVerifyMode=none
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base=(null)
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base-class=(null))
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 = <0x0x56052f694c80[NGImap4Client]: login=mwehr@fwsmail.de(pwd) socket=<NGActiveSocket[0x0x56052fc42e50]: mode=rw address=<0x0x56052fc974f0[NGInternetSocketAddress]: host=369057c07bd2 port=38890> connectedTo=<0x0x56052fc97390[NGInternetSocketAddress]: host=172.22.1.250 port=143>>>
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: [ERROR] <0x56052fccaa20[SOGoMailAccount]:0> Could not connect IMAP4
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: 37.4.250.60 "POST /SOGo/so/mwehr@fwsmail.de/Mail/0/folderINBOX/view HTTP/1.0" 500 72/126 0.042 - - 0 - 14
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: [ERROR] <0x0x56052f7f7a10[NGImap4ConnectionManager]> IMAP4 login failed:
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 host=172.22.1.250, user=mwehr@fwsmail.de, pwd=yes
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 url=imap://mwehr%40fwsmail.de@172.22.1.250/?tls=NO&tlsVerifyMode=none
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base=(null)
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base-class=(null))
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 = <0x0x56052fce0e40[NGImap4Client]: login=mwehr@fwsmail.de(pwd) socket=<NGActiveSocket[0x0x56052fd6a4f0]: mode=rw address=<0x0x56052fd6a560[NGInternetSocketAddress]: host=369057c07bd2 port=38898> connectedTo=<0x0x56052fd6a3f0[NGInternetSocketAddress]: host=172.22.1.250 port=143>>>
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: <0x56052fdf28e0[SOGoMailAccount]:0> renewing imap4 password
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: [ERROR] <0x0x56052f7f7a10[NGImap4ConnectionManager]> IMAP4 login failed:
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 host=172.22.1.250, user=mwehr@fwsmail.de, pwd=yes
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 url=imap://mwehr%40fwsmail.de@172.22.1.250/?tls=NO&tlsVerifyMode=none
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base=(null)
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base-class=(null))
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 = <0x0x56052fd66f70[NGImap4Client]: login=mwehr@fwsmail.de(pwd) socket=<NGActiveSocket[0x0x56052fc4e250]: mode=rw address=<0x0x56052fc4e2c0[NGInternetSocketAddress]: host=369057c07bd2 port=38900> connectedTo=<0x0x56052fd25a10[NGInternetSocketAddress]: host=172.22.1.250 port=143>>>
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: [ERROR] <0x56052fdf28e0[SOGoMailAccount]:0> Could not connect IMAP4
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: 37.4.250.60 "GET /SOGo/so/mwehr@fwsmail.de/Mail/0/view HTTP/1.0" 200 17/0 0.044 - - 0 - 14
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: [ERROR] <0x0x56052f7f7a10[NGImap4ConnectionManager]> IMAP4 login failed:
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 host=172.22.1.250, user=mwehr@fwsmail.de, pwd=yes
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 url=imap://mwehr%40fwsmail.de@172.22.1.250/?tls=NO&tlsVerifyMode=none
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base=(null)
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base-class=(null))
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 = <0x0x56052fdee6c0[NGImap4Client]: login=mwehr@fwsmail.de(pwd) socket=<NGActiveSocket[0x0x56052fdecd60]: mode=rw address=<0x0x56052fd18c70[NGInternetSocketAddress]: host=369057c07bd2 port=38908> connectedTo=<0x0x56052fd18b70[NGInternetSocketAddress]: host=172.22.1.250 port=143>>>
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: <0x56052fc1a9a0[SOGoMailAccount]:0> renewing imap4 password
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: [ERROR] <0x0x56052f7f7a10[NGImap4ConnectionManager]> IMAP4 login failed:
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 host=172.22.1.250, user=mwehr@fwsmail.de, pwd=yes
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 url=imap://mwehr%40fwsmail.de@172.22.1.250/?tls=NO&tlsVerifyMode=none
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base=(null)
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 base-class=(null))
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 = <0x0x56052fdc9f30[NGImap4Client]: login=mwehr@fwsmail.de(pwd) socket=<NGActiveSocket[0x0x56052fdb3e20]: mode=rw address=<0x0x56052fdb3e90[NGInternetSocketAddress]: host=369057c07bd2 port=38910> connectedTo=<0x0x56052fc1b9f0[NGInternetSocketAddress]: host=172.22.1.250 port=143>>>
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: [ERROR] <0x56052fc1a9a0[SOGoMailAccount]:0> Could not connect IMAP4
sogo-mailcow_1 | Jul 23 15:28:55 369057c07bd2 sogod [67]: 37.4.250.60 "POST /SOGo/so/mwehr@fwsmail.de/Mail/unseenCount HTTP/1.0" 200 21/31 0.039 - - 0 - 14