Miscellaneous topics that do not fit into specific categories.
Sorry to hear that you’re having trouble with this situation. Users here can't contact you directly, unfortunately. Could you please share a little more information? Is this happening only when you try to sign in to the Microsoft 365 apps, or are you also unable to sign in to other Microsoft apps on the same device, such as the Microsoft Store?
Also, have you tried signing in to your Microsoft account through a web browser on the same device? If so, does the same issue occur there?
When you mention a “third party,” do you mean that you are being asked to use a different verification or sign-in method, such as an authenticator app, email, phone number, or security code?
If you receive any error message during the sign-in process, please share the exact message or a screenshot, making sure that no personal or sensitive information is visible.