No mail access on mobile devices any more

No mail access on mobile devices any more

Hello,

It seems that after the work you have done your servers, access via my mobile devices is no  longer granted. I have my email on my laptop without issues, even installed on a separate computer the account without issues but my cell phone (android) and my tablet (android) do not allow me in and keep on repeating the question that i should check my email address. 

It started with the request to re-enter my password. I took the accounts off and reinstalled them, did not work. I cleared cache, did not work, I installed on another laptop (Outlook), worked immediately. Installed on another phone (Android), did not work. 

What has changed and/or what can I change to solve this. It must have to do with the work you did. 

Thanks, 
Ronald