Cannot remove email channel

Infos:

• Used Zammad version: 6.2.0-1702975436.87754a02.focal
• Used Zammad installation type: package
• Operating system: Ubuntu 22.04.3 LTS
• Browser + version: Edge v120

Expected behavior:

• Should not see any artifact after deleting account in the email channel
• Should see a delete button in email channel as mentioned in documentation (Managing Accounts — Zammad Admin Documentation documentation)
  

Actual behavior:

• Cannot see the delete button
  

Steps to reproduce the behavior:

• Not sure how to reproduce this, we have switched from Email channel to Microsoft 365 channel and did Delete the email channel, but the Email channel still shows an Outbound account.

We had left it as it is because everything else works fine with Microsoft 365, and we have no usability issues. But from October 2023, with Microsoft disabling basic auth for SMTP, we are seeing this "Can’t use Channel::Driver::Smtp: #<Net::SMTPAuthenticationError:Net::SMTPAuthenticationError>

I’m sure Zammad is not using this channel at all because all communications are going through the Microsoft 365 channel successfully, and we see no errors in the M365 account configuration.