My Sent Items folder has been emptied and no longer saves sent emails. not simple. Outlook 2016

Question

I have been working on support for one of my clients and something is going wrong with Outlook 2016. As the title says, there are no sent items in the sent items folder and emails that are sent are not saved. The sent items folder just always says "We didn't find anything to show here."

This is an IMAP account. I have tried many different solutions through googling my issue, here are most of them:

I have unchecked and checked the "save copies of sent emails to saved items folder" and restarted Outlook in between.

I have removed and readded the email account in question.

I have changed the ROOT directory in account settings to "Inbox".

I have repaired Microsoft Office.

I have checked the size of the folder to make sure it was not the view causing the problem, the size was 0kb.

If someone could help me please, I have put so many hours into this problem and I feel like there is a dumb explanation/solution... Thank you in advance.