Accidentally marked spam as non-spam in Outlook 365

Hey cccp31 ,

I am afraid there is no way to reset the junk filter, Here is what you can do, first via outlook, modify the following two settings under junk options :

An entire domain can be blocked via OWA, if you are looking to do that:

https://support.microsoft.com/en-us/office/block-senders-or-unblock-senders-in-outlook-on-the-web-9bf812d4-6995-4d19-901a-76d6e26939b0

The first section in above article holds good for domains as well as senders, if you don't see the add button while adding a domain just type the domain name and press enter to add it.

Lastly if you have admin rights to your tenant you can create a transport rule to send emails to junk based on a text pattern in senders email address:

https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/use-transport-rules-to-configure-bulk-email-filtering?view=o365-worldwide