How to fix email box full 100% after applying and E5 license

Hi @Eric Thomas 
Thank you for reaching out to Microsoft Learn Q&A!   
Based on your description, I understand that one of your users has reached their mailbox quota, and the archive feature is not functioning as expected. 

To provide the most accurate support, I’d like to ask some questions to better understand your situation: 

Question 1: Regarding the "Archive" feature mentioned in your inquiry, could you please confirm which option you are referring to: 

The Archive folder in Outlook (as shown in the image below), 

or the In-Place Archive mailbox (as shown in the second image)?

If you are referring to the In-Place Archive, may I confirm whether it has been enabled and has reached the 1.5TB storage limit? 

If the archive mailbox has not yet been enabled, you can refer to the following Microsoft Learn article for detailed instructions: Enable archive mailboxes for Microsoft 365 | Microsoft Learn 

Question 2: You mentioned that the issue began after assigning an E5 license to the affected user. Could you please clarify: 

+Is the affected user a newly created account, or was the license changed from a previous plan? 

+If it was a license change, what was the original license assigned to the user before switching to E5? 

Additionally, could you please verify whether the user's mailbox storage has updated to 100GB, which is included as part of Exchange Online Plan 2 (a feature of the E5 license)? 

In the meantime, to help restore normal email delivery, you can free up some mailbox space by: 

+Emptying the Deleted Items folder after deleting emails from other folders. 

+Using Shift + Delete to permanently remove items, which sends them directly to the Recoverable Items folder. 

Please know that while our initial response may not resolve the issue immediately, we are committed to working with you to find the best possible solution. Any updates, additional context, or follow-up questions you provide enable us to refine our guidance and offer more accurate support; not only for you, but for others in the community who may be experiencing similar issues. 

Please feel free to reach out at any time. We sincerely appreciate your input and are here to assist you to the best of our ability 

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