neomutt oauth stopped working

Since last week oauth2 just stopped working. It did a while before and healed itself mysteriously and I am eager to find out what is happening here. I installed thunderbird for reference and it is working — receiving and sending emails is possible with oauth2. I have an MS Office account and configured the authentication making use of mutt_oauth2.py script linked in the docs following the steps outlined in the README . Running the script manually yields a token. Testing suggests, imap and smtp communication is basically working (the script seems to log in successfully if I am correct).

/home/me/bin/mutt_oauth2.py /home/me/.neomutt/token --provider microsoft --verbose --test
[…]
IMAP authentication succeeded
POP authentication succeeded
SMTP authentication succeeded

And neomutt was working as well – however stopped to do so a few days ago. Logs tell

[2023-06-18 10:35:17] mutt_socket_write_d() 4> c0000 CAPABILITY
[2023-06-18 10:35:17] mutt_socket_readln_d() 4 cmd_parse_capability() Handling CAPABILITY
[2023-06-18 10:35:17] cmd_parse_capability()  Found capability "IMAP4": 0
[2023-06-18 10:35:17] cmd_parse_capability()  Found capability "IMAP4rev1": 1
[2023-06-18 10:35:17] cmd_parse_capability()  Found capability "AUTH=XOAUTH2": 9
[2023-06-18 10:35:17] cmd_parse_capability()  Found capability "SASL-IR": 13
[2023-06-18 10:35:17] cmd_parse_capability()  Found capability "IDLE": 12
[2023-06-18 10:35:17] cmd_parse_capability()  Found capability "NAMESPACE": 4
[2023-06-18 10:35:17] mutt_socket_readln_d() 4 imap_cmd_step() IMAP queue drained
[2023-06-18 10:35:17] imap_authenticate() Trying user-defined imap_authenticators
[2023-06-18 10:35:17] imap_authenticate() Trying method oauthbearer
[2023-06-18 10:35:17] mutt_sasl_client_new() SASL local ip: 2001:db8::1;38986, remote ip:2001:db8::2;993
[2023-06-18 10:35:17] mutt_sasl_client_new() External SSF: 256
[2023-06-18 10:35:17] mutt_sasl_cb_log() SASL: No worthy mechs found
[2023-06-18 10:35:17] imap_auth_sasl() oauthbearer unavailable
[2023-06-18 10:35:17] imap_authenticate() Trying method xoauth2
[2023-06-18 10:35:17] imap_auth_oauth_xoauth2() Authenticating (XOAUTH2)...
[2023-06-18 10:35:17] msgwin_recalc() recalc done, request WA_REPAINT
[2023-06-18 10:35:17] msgwin_repaint() repaint done
[2023-06-18 10:35:17] ibar_recalc() recalc done, request WA_REPAINT
[2023-06-18 10:35:17] helpbar_repaint() repaint done
[2023-06-18 10:35:17] menu_repaint() repaint done
[2023-06-18 10:35:17] ibar_repaint() repaint done
[2023-06-18 10:35:17] mutt_account_getoauthbearer() OAUTH token is too big: 2304
[2023-06-18 10:35:17] msgwin_recalc() recalc done, request WA_REPAINT
[2023-06-18 10:35:17] msgwin_repaint() repaint done
[2023-06-18 10:35:17] mutt_sasl_client_new() SASL local ip: 2001:db8::1;38986, remote ip:2001:db8::2;993
[2023-06-18 10:35:17] mutt_sasl_client_new() External SSF: 256
[2023-06-18 10:35:17] mutt_sasl_client_new() External authentication name: karl.liebich@ida.me
[2023-06-18 10:35:17] mutt_sasl_cb_authname() getting authname for outlook.office365.com:993
[2023-06-18 10:35:17] imap_auth_sasl() xoauth2 unavailable
[2023-06-18 10:35:17] imap_authenticate() No authenticators available or wrong credentials

- libsasl2 related packages have last been updated in March so there was no change. - Neither was in my neomutt configuration or password. - The OAUTH token is too big: 2304 message is known and did not have any impact in the past. --- Any hints on how to debug this any further and what to do about it?