how many devices does the Arlo app allowed to be logged in at a time?

[TomMac · Accepted solution]

If more than one logs in using the primary name/pw the second will bump out the first.

If you need more than one user at the same time, the primary holder must share...SETTINGS>GRANT ACCESS...

This will allow mutli users. 

As to how many, last I heard it was more than 6 shared ( or no limit ).  Just more users = less battery life.