Background: I think Archivebot should more clearly notify users of problems. Typical causes of failures include invalid syntax in the template and abuse filters. If it fails to remove sections from the main page repeatedly, it could pile up a mess in the archive. [1]

Proposal: When archivebot.py fails to archive a page, it should leave a marker there. The bot should then skip the page unless the marker is removed. The marker serves as a request to ask someone to fix the underling problem and then remove the marker (and report a bug if they are sure something is wrong on the bot's side)

Example:

{{Auto archiving
|old=7d
|archive=User:Example/Archive
|}}

could be modified into

{{Auto archiving
|old=7d
|archive=User:Example/Archive
|suspend=yes <!-- Archiving suspended; please see https://www.mediawiki.org/wiki/Manual:Pywikibot/archivebot.py/suspend -->
|}}

and https://www.mediawiki.org/wiki/Manual:Pywikibot/archivebot.py/suspend should give further explanations and suggest possible ways to fix it.

Alternatively the bot could leave a message at the bottom of the discussion page.

The notification should be done as a non-bot edit.

[1] https://commons.wikimedia.org/w/index.php?title=User_talk:Ahonc/Archives/January_2016&action=history