one of my email accounts won't allow me to block junk mail senders anymore

Question

one of my email accounts won't allow me to block junk mail senders anymore

Dave B 0

It only does this in one of my accounts, the others still allow me to block emails in my junk mail folder, or in my inbox. No matter what email I try to block I get the msg "Can't block sender - We couldn't block this sender, please try again later". I try later and it still won't let me block them. I've closed and reopened Outlook and restarted my computer. I've run antivirus scans. Nothing fixes this.

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2 answers

Your answer

Answer 1

Dave B 0

The problem occurs in both versions of Outlook. I've found that if I move them to the Inbox, then "Report" them as junk and block them, that works. I just have to manually delete them from the Junk folder.

Winnie-B 9,930 Reputation points Microsoft External Staff Moderator

2026-08-03T07:15:19.4066667+00:00

Hi Dave B

Thank you for the update.

As a workaround, you can continue using the method you've discovered: move the message to the Inbox, use Report > Junk and block sender, then delete the message afterward.

To help narrow this down further, could you confirm whether the same behavior occurs with all messages in the Junk Email folder, or only with messages from certain senders? Also, if possible, does the issue occur when right-clicking a message in Junk Email and selecting Block, or only when using the toolbar button?

That information may help determine whether this is related to a specific message type, sender, or the Junk Email folder itself.
Dave B 0 Reputation points

2026-08-03T09:58:28.2533333+00:00

Any email I try to block on this account, gives me the error msg. It does it in Junk mail, Inbox and Deleted folders. Whether I use the Block button or right click and choose "Block", doesn't matter. Same msg. The only way I can block a msg is to move it out of the Junk folder, "Report" it as Junk and block it that way.
Winnie-B 9,930 Reputation points Microsoft External Staff Moderator

2026-08-04T04:46:35.79+00:00

Good day Dave B

Thank you for the additional details.

As a test, please open Settings > Mail > Junk email and try manually adding a sender's email address under Blocked senders and domains. If the same error occurs there, it would further indicate an issue with the mailbox's blocking functionality rather than with a specific message.

If manual addition also fails, and since you've already confirmed the issue across multiple Outlook interfaces, this may require investigation by Microsoft Support, as community troubleshooting options would be largely exhausted at that point.

Please let me know whether manually adding a blocked sender in the Junk Email settings works or produces the same error.

Answer 2

Hi Dave B

I understand that only one of your Outlook.com accounts is affected, while your other accounts can still block senders normally. The error message "Can't block sender - We couldn't block this sender, please try again later" suggests there may be an issue with the block list or account settings for that specific mailbox.

To help narrow this down further, could you please confirm:

Does the error occur when accessing the account through Outlook.com on the web, or are you using New Outlook for Windows?
When did the issue first start?
Are you able to manually add addresses to the blocked senders list, or does the same error appear there as well?

In the meantime, please try the following:

Sign in to Outlook.com and open “Settings” > “Mail” > “Junk email.”
Check whether the “Blocked senders and domains” list is unusually large. If so, try removing a few old entries and test blocking a sender again.
Instead of using the right‑click Block option, manually add the sender's email address to “Blocked senders and domains” and check whether it saves successfully.
Open the affected account in an InPrivate/Incognito browser window or a different browser and test again.

For reference, you can see Microsoft's junk email settings documentation: Block or unblock senders in Outlook