Hi,
Thank you for posting in Microsoft Community.
It seems that you’ve reached the storage limit on your 50GB mailbox. Unfortunately, there is no way to increase the storage limit. Microsoft 365 Family and Microsoft 365 Personal subscribers get 50 GB of storage space at most
However, there are several ways to free up space in your mailbox so that your account can sync again:
- Clean up your mailbox: From the Settings > Storage page, you should see a breakdown of how much space each folder in your mailbox is taking. Below, you should see a list of the folders represented in the breakdown with the option to permanently delete all items (or those older than 3, 6, or 12 months) in these folders to free up space.
- Permanently delete email: When deleting items from Inbox or other folders, items are sent to the Deleted Items folder by default. The Deleted Items folder does count against your mailbox storage quota until it is manually emptied or the emails are automatically deleted after 30 days, whichever happens first. Note: Items in the Junk folder are automatically deleted after 10 days. To permanently delete a message or messages, select or highlight the messages, press Shift and DEL on your keyboard.
- Sweep unwanted email from your inbox: Use the Sweep button to quickly remove unwanted email from your inbox or archive folders. Sweep lets you automatically delete all incoming email from a particular sender, keep only the latest message from that sender, or delete email that’s older than 10 days. To sweep your inbox, choose a message you want to sweep and select Sweep.
- Saving attachments to OneDrive is another good way to make room in your inbox: At the top of your message list, select Filter > Sort by > Size. Select the message containing the attachments you want to upload to OneDrive. Beneath the attachment, select Save to OneDrive.
If you need more than 50 GB of mailbox storage space, the only possible option is by upgrading to an Exchange Online Plan 2 license which will increase the mailbox storage limit from 50 GB to 100 GB.
Thank you for your understanding
Sincerely,
Leonardo_Y