is it a problem to have multiple people log on as a teacher with the same password from different IP addresses?

Hi

I am an educational assistant and the teacher I work under shared his login and password info with the 3 EA's in his classroom. We were able to log in for a week or so, but now cannot. What I and the other EA are seeing is that the home page will not load and also if I search for the login page it says that the user name/password is incorrect. Teacher did not change the password or user name. Just trying to troubleshoot. 

Is there any security feature built into your login system that would account for these problems, like it recognizing multiple people using the same user/password from IP addresses all over town? 

I created my own teacher login to be able to create this query. When I logged in this way I chose "Continue with google". If the teacher used "Continue with google" at his ISP while logged into google and I tried to log in while logged into my own different google account could that be the issue?

Thanks,
Kate