Dear @David-9975,
Good day, and I appreciate the clear explanation of your concern. As a forum moderator, I genuinely wish I could directly access your account or delve into the backend systems to diagnose and fix this for you. However, our role here is limited to providing general guidance and solutions that can be applied by users.
I attempted to reproduce the issue in my test environment but in my case, I was able to edit the blocked senders list and block an entire domain without encountering any errors. I also did not find any recent reports of a similar issue, which suggests this may be a temporary or environment-specific behavior.
In the meantime, you may try the following steps to see if they help:
- Open Outlook on the web in Incognito/Private browsing mode.
- Clear the browser cache specifically for outlook.office.com and office.com, then try again.
- Wait around 10–15 minutes and retry, as this could be a temporary backend issue.
If the issue persists, you can try switching back to Classic Outlook and performing the change there:
- In the New Outlook desktop app, toggle off “New Outlook” in the top-right corner to switch to Classic Outlook.
- In Classic Outlook, locate the Quick Access Toolbar at the top left, then select Junk > Junk Email Options.
- If the Junk option is not visible:
- Go to File > Options > Quick Access Toolbar.
- Change the dropdown to All Commands.
- Locate Junk, click Add >>, and ensure that Show Quick Access Toolbar is checked, then select OK.
- Open the Blocked Senders tab and edit or remove the entries as needed, this usually works without the error.
I hope this information helps clarify the situation and provides you with workable solutions. Should you have any further questions or need additional assistance, please don't hesitate to reach out. I'm always happy to help. Have a wonderful day!
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