Hi @Elliott Chandler ,
Welcome to our forum!
What operating system do you use?
What's the version of your Outlook 365? (File > Office Account > About Outlook). Please make sure you have upgraded your Outlook 365 to the latest version.
To further confirm that the problem is only related to the outlook client, does the issue only occur when opening Outlook notifications? If so, does this issue occur recently or has it always existed? If it happened recently, did you carry out any special operations before that?
According to the use of my Outlook 365(version 2108(Build 14326.20238 Click-to-Run)) client in win10 system, the emails can be opened successfully when I click outlook notifications. Considering the impact of some add ins, It is suggested that you try to start outlook in safe mode(win+R>type: outlook /safe) to check whether it works normally.
If the issue still occur in safe mode, considering that the outlook program itself has been damaged, it is recommended that you try to fix the office application or uninstall and reinstall office to check if there're any differences.
Hope to help you! If the above does not work, please provide more relevant information.
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