I am currently using an iPhone 6, all software updates have been installed. This morning when I attempted to open my apple email by using the build in mail app on IOS I was greeted with the "Welcome to Mail" screen. Providing me with options to setup an email account. (iCloud, exchange, Google etc.) I thought this strange since I have been using this iPhone for over a year and have had my mail setup for all of that time. I tapped the iCloud mail option, typed in my email address and password. As the account was attempting to be verified, a small box appeared saying "mail account already attached to this iPhone. After several attempts of trying to log in, it continued to not allow me with the same error message.
I then did some searches and read some posts about how to remove your email account then re-entering the information to log back in. However, this Apple mail account is my iCloud account, attached to iMessage and other options. IOS will not permit me to remove this account from the iPhone.
I am stuck, unsure of how to correct this problem. To provide you with additional information, I do log onto my Apple mail account through my Windows Laptop, I do this through the website not using ITunes of downloaded programs. I have done this the entire time I have had an Apple device. No changes were made to my iPhone recently, and the mail app worked correctly yesterday.
Any help would be greatly appreciated.
iPhone 6, iOS 11.2.6