[Bug]: `Error: Undefined array key` [..] `at [..]/apps/mail/lib/Service/Classification/NewMessagesClassifier.php#92`

[iamhives]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

[PHP] Error: Undefined array key 234626 at /home/xxx/nextcloud/apps/mail/lib/Service/Classification/NewMessagesClassifier.php#92
from ? by -- at Feb 28, 2025, 12:00:09 AM

Steps to reproduce

1. Unknown. Have about 240 logged errors in the past few days. Perhaps created each time a new email is downlaoded/accessed?

Expected behavior

[PHP] Error: Undefined array key 234626 at /home/xxx/nextcloud/apps/mail/lib/Service/Classification/NewMessagesClassifier.php#92
from ? by -- at Feb 28, 2025, 12:00:09 AM

Nextcloud Server version

30

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

MySQL

Is this bug present after an update or on a fresh install?

Updated from a MINOR version (ex. 32.0.1 to 32.0.2)

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

List of activated Apps

Mail 4.2.2  Recently updated to 4.2 and then 4.2.2 and log entries seem to have appeared since then?

Nextcloud Signing status

Nextcloud Logs

Additional info

No response

[iamhives]

I had an error when updating to Mail 4.2 that I logged here previously as a bug