"Authentication Error" on mobiles connecting to Orbi RBK-50

I have a netgear Orbi RBK-50-100PES with 2 satelites, with some problems. All our Samsung mobiles (and one sony mobile) we keep getting disconnected from the main Orbi wifi network:

• I receive the message “authentication error”, but the username and password is 100 % correct. Sometimes if I turn on/off the wifi, it works again. Sometimes it works a few hours later.
• The username and password is correct and the same both when it works and when it does not work.
• The problem is only on the Orib main wifi network. The Orbi guest wifi network works fine, I receive no authentication error there.
• The problem is only with mobile phones, other devices works fine.
  
  How do I fix this? I need both the Orbi main wifi network and the Orbi guest wifi network to work stable with mobile phones and other equipment.