@dinhdinh666 Hello, signal strength can play a factor regarding connectivity and issues with logging in. How close are you to the WiFi hotspot when this is happening? Also, are you physically moving while using this WiFi hotspot or are you in a stationary position? Will you be able to email us at firstname.lastname@example.org? We may need to obtain additional information, for instance, the username you're using to log in. -Kevin M. Cox Support Forum Moderator
I don't know how far I am from the WiFi hotspot, but my computers (windows 10) show that the signal strength is good. The computers sit on a table, so no I'm not moving around. I'll send a copy of this forum post to that email address.