Getting error while creating new user with a non-interactive shell

Cloud AZURE
#1

i was asked to create a user named mark with a non-interactive shell on App Server 2. I given below command
sudo useradd -s /sbin/nologin mark

but while checking (clicking Check) am getting error and task is incomplete and window is closing , how do i proceed. what is the error explanation here?

#2

It would help us a lot if you could share a screenshot of the steps you took and the error.