Hi not sure if the upgrade is a red herring but I had some issues last week trying to add a diffreent domain to my account but deleted that in the end.

in my outlook 365 on my computer (Not OWA) I deleted the hello@openformula account then tried to Add back again.

It doesn't matter what setting I try I simply cannot get it to connect.  I also have  Outlook installed on my laptop which is sending and receiving OK.

Please could you investigate why Outlook will not connect

for info one ofthe errors I get is

smtp server response 530 5.5 1 authentication required

I know I am using the right login details because I used them to login in to Zoho online with the same username and password

thanks