External forwarding in Microsoft 365

If you have previously, or recently, added a forward to an external address on one of your 365 hosted mailboxes you may receive an NDR in the forwarding mailbox along the lines of ‘550 5.7.520 Access Denied. Your organization does not allow external...

Excel add-in keeps reloading

Having removed a (non-existent) add-in from Excel, when you restart the program the add-in still tries to load and throws an error because it doesn’t exist. To ensure it is goes away, and stays away, remove the add-in from Excel as normal, close Excel, then...