I am using one plus two device since 3 months, i have android version 5.1.1 and Oxygen Os: 2.2.0
sometime my mobile hangs and going to blank...
its my corporate account..
I dont have remove option there
I have tried to delete my Gamil(IMap) account by navigating to Settings -> Accounts -> Touch on the Gmail(Imap) account and clcik on three dots...
I got one from this sale
sometime its due to updates on your apps..check with your apps
Thanks for the update