Do you have hidden Outlook rules that you need to remove from your system because it is sending all incoming emails to your Deleted Items folder? I have had this issue where all incoming emails went to the Deleted Items folder and was fortunate to have it resolved.
Before following my instructions, you may want to export the rules that are currently saved as you can import them later on instead of re-inputting manually.
Removing Hidden Outlook Rules
Please try and bring up the Run window. Once the Run window is visible, type in outlook.exe /cleanrules and submit the command to execute. Once the process is over, you can open Outlook and see if the yellow triangle is gone.
Now that your rules have been removed from Outlook, try and send an email to yourself and see if it ends up in the Deleted Items folder. If it is fine, you can import any rules that you had backed up and submit another email to yourself. If no issues after the import, then your issue has ben resolved but if the issue returns, you will need to add your rules manually and then backup for safe keeping.