What you’re seeing
- Outlook shows a banner saying the shared mailbox is full or almost full, and the storage bar sits at or near 50 GB.
- Customers who email info@ or accounts@ get a bounce saying the recipient's mailbox is full.
- Staff can still read old mail in the shared mailbox, but new messages stop arriving and sent items fail to save.
- The Microsoft 365 admin center or a consultant says the mailbox now needs its own license, and nobody is sure which one.
Common causes
Every environment is different, but these are the causes our engineers find most often:
- Shared mailboxes are free only up to 50 GB; going beyond that requires an Exchange Online Plan 2 license, or Plan 1 with the archiving add-on.
- Years of attachments, scanned documents and automated notifications pile up because nothing ever moves or deletes old mail.
- No online archive was ever enabled, so every message stays in the primary mailbox and counts toward the cap.
- Litigation hold or a retention policy keeps deleted items around, so cleanup by staff does not actually free space.
- People sign in to the shared mailbox directly with its own password, which Microsoft's terms say requires a license regardless of size.
Why it matters
Shared mailboxes are usually the front door of the business: the address printed on invoices, the website contact form and supplier statements. When one fills up, incoming orders, payment remittances and customer questions bounce back to the sender, and many of those senders simply give up. Buying the wrong license wastes money every month, while letting the mailbox stay full quietly costs revenue and goodwill. Deleting mail in a panic can also destroy records you are required to keep.
How AskTechGurus fixes it
Skip the trial and error. A certified engineer works on your actual system, finds the root cause, and fixes it properly.
Tell us what’s happening
Submit a ticket in about two minutes. Paste the error, describe what changed, and pick your tier. No charge to submit.
A certified engineer diagnoses it
A vetted, US-based systems engineer claims your ticket, usually within minutes during business hours, and investigates over a secure remote session you can watch and end at any time.
Fixed and verified with you
The engineer resolves the root cause and confirms with you that it’s working. You don’t just get a workaround, and you get a plain-English summary of what was wrong.
Pay only when it’s resolved
Fixed price from $99, invoiced only after you approve the fix. If it isn’t resolved, you don’t pay.
Frequently asked questions
Do we really have to pay for a shared mailbox now?
Only if it needs more than 50 GB, an online archive, a litigation hold, or direct sign-in. Under those conditions Microsoft requires a qualifying Exchange Online license on that mailbox.
Can't we just delete old email to get under the limit?
Sometimes, but retention settings may keep the deleted items counting against the quota, and you may be throwing away records you need. A planned archive is usually safer than a mass delete.
How can AskTechGurus help?
A certified US engineer reviews the mailbox size, retention and licensing in a remote secure session and recommends the cheapest option that keeps mail flowing. Pricing starts from $99 and you pay only when it's resolved.