I wrote a Python script that edits emails and appends them to a folder with the IMAP "APPEND" command. The emails are successfully "created" as I am able to fetch them from the destination folder after the execution of the APPEND command. The problem is that the newly created e-mails simply won't show up in Outlook. It is worth noting that the destination folder contains older e-mails (previously created with my script) which are still visible in Outlook. I removed all Outlook filters from the concerned folder but still there are no new emails showing up. I also pushed the "Update folder" button but still no success. There is probably some advanced Outlook configuration that I am missing here ;) I would appreciate some help.
I "solved" the problem by simply removing and re-adding the concerned account ("Account Properties" -> "Account Settings" --> "Remove"/"Add"). Now I will have to wait and check if the problem reappears.
If this does not solve the problem maybe try with another profile.