Hi my name is ***** ***** I will be the expert working with you today to help and resolve the problem you have posted.I am sorry to hear that you are having such trouble. I will try my best to help you out and resolve the problem as quick as possible.
What email service are you using?
Not all email services provider provides the multiple login in different devices as the system server detects that the email is being hacked if logged in to different devices.
Gmail provides multiple login service.
let me check if Fastmail.com provides multiple login facility.
I am working on it please stand by.
i can remote connect and check in your email settings if single login is allowed in multiple devices.
Click on the remote link and as it opens the page scroll down and click on the green button "I Agree" download and run Secure Remote AssistanceAllow it to install and let it be opened. I will be able to connect then.