An integrated threat protection solution designed to detect, investigate, and respond to cyber threats across Microsoft 365 services.
Hi Graeme,
I understand that you're having an issue with authenticating and it always the 2nd time around when you log in to your account you must enter your password and re-authenticate but I’m here to help.
I suggest first to allow the browser cookies whether your using chrome or edge just go to settings look for Cookies site permissions and ensure Allow all cookies or at least not blocked for https://login.microsoftonline.com, https://login.live.com and https://microsoft.com. Now be sure to disable the Clear cookies on exit and any extension that block cookies.
Next I need you to register your device as Trusted Device sign in to https://myaccount.microsoft.com go to Security Info and when prompted for MFA check the box that says “Don’t ask again for 30 days”
I hope this answer is helpful if you have further questions feel free to reply back
Regards,
Marcelo