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Can’t send email because your storage is full message. But storage is not full

Jay McCrea 0 Reputation points
2026-06-09T00:30:47.4+00:00

I’m trying to send email from my iPhone and the outlook app says “Can’t send email because your storage is full” and outlook doesn’t let me send emails. I check my storage on outlook.com and one drive and I have 2.5gb free.. what is going on here? I’ve already tried “reset account” in the settings menu, that did nothing… any help would be appreciated as I desperately need to send some emails this morning.

Outlook | Outlook for mobile | Outlook for iOS | For home
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  1. Victor1-V 9,185 Reputation points Microsoft External Staff Moderator
    2026-06-09T06:24:18.3833333+00:00

    Hello Jay McCrea,

    I understand that Outlook for iOS says your storage is full even though Outlook.com and OneDrive both show available space. Please note that this is a user-to-user forum, so contributors do not have access to your account or backend storage status, but the behavior can be narrowed down with a few checks.

    The Q&A Assist answer is generally correct that both Email storage and Microsoft storage can affect sending in Outlook.com. If you have not had a chance to try it yet, please first confirm both storage sections are under quota from the Outlook.com storage page: Storage limits in Outlook.com.

    I would also suggest one quick test:

    1. Sign in to Outlook.com from a browser: https://outlook.live.com/.
    2. Try sending a small test email without attachments.
    3. If the message sends from Outlook.com on the web, the account storage is likely not blocking sending, and the issue is more likely with the Outlook for iOS app session or mobile sync state.
    4. If only the iPhone app is affected, try updating Outlook for iOS first. If it is already updated, remove the account from Outlook for iOS and add it again. This is different from only using “Reset account,” because it rebuilds the account connection in the app.

    For reference, Microsoft’s article also notes that if only one device cannot send or receive mail, removing the mobile device partnership can help with sync-related issues: Can’t send or receive email in Outlook.com.

    If it also cannot send from the web, even though both storage areas show available space, please contact Outlook.com support from the web version for further assistance:

    1. Go to Outlook.com and sign in.  
    2. Click the Help icon (question mark) in the top right corner.  
    3. In the Help pane that opens, type a brief description of your issue (e.g., "cannot send emails"), then press Enter.   
    4. Scroll down the page until you see "Still need help?", click Yes.   
    5. Select "Chat with a support agent in your web browser."  
    6. Review the description of your issue and confirm your email address (ensure it's an email you can access).  
    7. Click Confirm to create the service request and then Start chat to connect with an agent.  
    8. The screen will indicate that your request has been submitted and the system is connecting you to Outlook.com live chat support, which may take a moment to load.  

    I hope this helps.

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  2. AI answer

    2026-06-09T00:31:26.8833333+00:00

    The message “Can’t send email because your storage is full” on Outlook for iOS while Outlook.com and OneDrive both show free space is typically caused by how Microsoft unified storage and client apps interpret storage status, or by a client-side issue on the device.

    Key points from the provided information:

    1. If Microsoft cloud storage (OneDrive + Outlook.com unified storage) is considered full, sending and receiving email is blocked across Outlook.com and clients, even if email storage alone is not full.
      • When Microsoft unified storage is exceeded:
        • Email cannot be sent or received in Outlook.com.
        • OneDrive becomes read-only and new uploads are blocked.
      • This is described under “Microsoft Unified Storage is full” and “Microsoft storage FAQs”.
    2. Outlook and Outlook.com explicitly block sending/receiving email when cloud storage or mailbox storage is full.
      • Messages sent to an account while storage is full are bounced and unrecoverable until storage is back under quota.
    3. OneDrive being full (or seen as full) can also block email sending.
      • If either Outlook.com mailbox or OneDrive storage is full, email sending/receiving is blocked.
    4. There are known client-side issues where mobile apps show “mailbox is full” or similar errors even when server-side limits are not actually exceeded.
      • For Exchange + iPhone Mail, Microsoft has identified such issues as client-side and directs users to contact Apple.
      • For Outlook mobile, similar behavior can occur after app updates and is resolved by app updates or client resets.
    5. In similar storage-related issues, unlinking and relinking OneDrive or waiting for storage status to refresh has resolved “storage full” errors.
      • Users have resolved “storage exceeded” or “storage showing full” issues by:
        • Unlinking OneDrive from the device, deleting a problematic file, and relinking.
        • Waiting 24–48 hours after freeing space or purchasing storage for the status to propagate.
        • Resetting or re-adding accounts in Outlook apps.

    Based on this, the most likely causes and steps are:

    1. Unified storage status not yet refreshed
      • Even if Outlook.com and OneDrive show 2.5 GB free, the unified storage status used by Outlook mobile may still be cached as “full”.
      • After freeing space or changes to storage, it can take up to 24–48 hours for the status to update across all services and apps.
    2. OneDrive or unified storage previously exceeded quota
      • If at any point OneDrive or Outlook.com storage exceeded the quota, email sending is blocked until the account is back under quota and the status has propagated.
    3. Client-side issue in Outlook for iOS
      • Similar to the documented iPhone Mail issue (“Cannot Send Mail – Your mailbox is full”), Outlook for iOS can misinterpret server responses or cached storage data and show a full-storage error even when the server reports free space.

    Recommended actions, aligned with the context:

    1. Verify unified storage and mailbox status
      • Confirm that both Outlook.com mailbox and OneDrive are under their quotas using the mailbox storage page and OneDrive storage page referenced in the documentation.
      • Ensure no shared folder or expired promotion has pushed OneDrive over quota.
    2. Free additional space as a safeguard
      • Even with 2.5 GB free, delete or move some files from OneDrive and clean up large or old emails (especially with large attachments) to increase the margin below the quota.
      • This ensures the account is clearly under any threshold the service might be using.
    3. Allow time for propagation
      • After freeing space or changing storage, wait up to 24–48 hours for the unified storage status to synchronize across Outlook.com, OneDrive, and Outlook mobile.
    4. Refresh the client state
      • Since “reset account” in Outlook for iOS was already tried, additional client-side steps that are known to help in similar storage-sync issues include:
        • Sign out of the account in Outlook for iOS and sign back in.
        • Remove the account from Outlook for iOS and add it again.
        • Ensure the app is updated to the latest version (as similar issues on iPad were fixed by a subsequent Outlook app update).
    5. If the issue persists after storage is clearly under quota and time has passed
      • Given that similar “mailbox full” errors with mobile clients have been identified as client-side issues, if Outlook for iOS continues to show the error while Outlook.com web works normally, the problem is likely with the app.
      • In that case, continue using Outlook on the web or another client temporarily until an app update resolves the behavior.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

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