You want to delete an email, but the process terminates with an error message? Then you have probably reached your storage space limit. As a result, emails can no longer be moved to the recycle bin when deleted, which is why the deletion process is aborted.
To delete emails and free up storage space again, activate the option "Remove deleted emails irrevocably" in the WebMail settings:
Log in to 1&1 IONOS WebMail.
Click the menu icon (System Menu) and then click Edit Settings.
Click on Email and check Remove deleted emails irrevocably. The settings are saved automatically.
Deleted emails are no longer saved as copies in the recycle bin and can therefore no longer be restored.