CRAM-MD5 authentication failed type 'exceptions.IOError'

[schossel]

Hi,
I'm running a script to save mails offline for roughly 15 accounts at the same domain. This worked flawlessly for about 2 years.
Since 2-3 weeks ago only 1 of the accounts has a problem. The script is running once an hour from 8 - 16 a clock. About half the time it works and the other half the following error comes up:

Args: /usr/bin/offlineimap -c /home/pi/mail_backup/config/kalt/[email protected] -l /home/pi/mail_backup/logs/kalt/[email protected]
2020-09-22 14:35:01 INFO: imaplib2 v2.57 (system), Python v2.7.16, OpenSSL 1.1.1g 21 Apr 2020
2020-09-22 14:35:01 INFO: *** Processing account [email protected]
2020-09-22 14:35:01 INFO: Establishing connection to mx2f8c.netcup.net:993 (mark.mueller)
2020-09-22 14:35:03 WARNING: CRAM-MD5 authentication failed: command: AUTHENTICATE => socket error: <type 'exceptions.IOError'> - Too many read 0
2020-09-22 14:35:03 WARNING: PLAIN authentication failed: connection closed
2020-09-22 14:35:03 WARNING: LOGIN authentication failed: connection closed
2020-09-22 14:35:03 ERROR: ERROR: All authentication types failed:
CRAM-MD5: command: AUTHENTICATE => socket error: <type 'exceptions.IOError'> - Too many read 0
PLAIN: connection closed
LOGIN: connection closed
2020-09-22 14:35:03 INFO: *** Finished account '[email protected]' in 0:01
2020-09-22 14:35:03 WARNING: ERROR: Exceptions occurred during the run!
2020-09-22 14:35:03 WARNING: ERROR: All authentication types failed:
CRAM-MD5: command: AUTHENTICATE => socket error: <type 'exceptions.IOError'> - Too many read 0
PLAIN: connection closed
LOGIN: connection closed

This started with the offlineimap version I was running before (I think 7.16?!). The I updated to 7.3.3 just to try something but the error persisted and I can't figure out why it even started or how I could get rid of it.

Any help would be much appreciated!

General informations

• system/distribution (with version): Rasbpian
• offlineimap version (offlineimap -V): 7.3.3.
• Python version: 2.7.16

Configuration file

[general]
accounts = [email protected]
pythonfile = ~/mail_backup/getpass.py

[Account [email protected]]
localrepository = local_externalHDD
remoterepository = mark.mueller

[Repository local_externalHDD]
type = Maildir
localfolders = ~/mail_backup/files/[email protected]/
sync_deletes = no
utime_from_header = yes

[Repository mark.mueller]
type = IMAP
remotehost = mx2f8c.netcup.net
remoteuser = [email protected]
remotepasseval = get_pass("[email protected]")
tls = yes
ssl = yes
maxconnections = 3
cert_fingerprint = 57de438708d7297ne75wg10917cb17d4d2deac7d0
ReadOnly = True
sync_deletes = no
folderfilter = lambda folder: folder not in ['INBOX.Trash','INBOX/Trash','INBOX.Junk','Junk','Trash','Spam']

REMOVE PRIVATE DATA.

pythonfile (if any)

REMOVE PRIVATE DATA.

Logs, error

Traceback:
File "/usr/share/offlineimap/offlineimap/accounts.py", line 293, in syncrunner
self.__sync()
File "/usr/share/offlineimap/offlineimap/accounts.py", line 372, in __sync
remoterepos.getfolders()
File "/usr/share/offlineimap/offlineimap/repository/IMAP.py", line 452, in getfolders
imapobj = self.imapserver.acquireconnection()
File "/usr/share/offlineimap/offlineimap/imapserver.py", line 583, in acquireconnection
self.__authn_helper(imapobj)
File "/usr/share/offlineimap/offlineimap/imapserver.py", line 456, in __authn_helper
"failed:\n\t%s"% msg, OfflineImapError.ERROR.REPO)

REMOVE PRIVATE DATA.