iOS & MacOS - Outlook o365 - http 1.1 Service Unavailable

Hi,

We have a lot of iOS devices, the all get a http 1.1 Service Unavailable after the user input email and password.

If the user goes back and try again, the app skip email and password and goes to the MFA.

Today I found a workaround on a MacOs trying login to Skype for Business, again after email and password, I get the http 1.1 page, if I right click and reload, I get MFA.

After that it works, until next time user have to change password, and thy have to login again :(

I can see others have the same problem here on the MS's Community forum.

On Android or Windows we havn't seen the error, only on iOS and MacOS.

https://answers.microsoft.com/en-us/msoffice/forum/msoffice_outlook-mso_imobile-mso_o365b/ios-macos-http-11-service-unavailable/963a5f80-dac1-45d0-812b-fe636a89daec

Tried to get help at MS's forum, they think I should contact Apple support, but I can't seem to find a way to contact Apple business support, anyone here know a fix?

Kind regards,

Flemming