Why does Google Colab say I have too many sessions?

Question

I'm trying to run two notebooks on Google Colab but could only connect one notebook at a time to the virtual machine. There's a pop-up message saying "Too many sessions. You have too many active sessions. Terminate an existing session to continue." when I click the "connect" button on the second notebook. Does anybody know why?

Screenshot:

Edit: I'm using Google Chrome on Windows 10

Edit March 3, 2020: I ended up not using Colab that day, but I came back the next day and was able to run two Colab notebooks just fine. strange. I had this issue a couple of times since I posted this question, but the error disappeared the following day.

Answer 1

I am used to use it with 2 active sessions. I mean, it gives that error when I try to connect for the third notebook. Today, however, I could only connect 1 notebook at a time. It does not permit the second connection. Therefore, the limit changes time to time.

Answer 2

I have the same problem and I found my solution in this issue. I change the Runtime Shape to Standard in the 2nd notebook, it worked for me.