Accessing Facebook chat via Psi+: repeated "suspicious login attempts"

Accessing Facebook chat via Psi+: repeated "suspicious login attempts"

I am using Psi+ Jabber client to use Facebook chat service.
Recently it began refusing login attempts several times a day, without
understandable reason when it would happen again.
When entering Facebook, I see message about suspicious login attempt from
unknown device - confirm it's OK, choose "Remember that browser" (?)
option, but in several hours or even minutes it all starts anew.
Is it a new authentication feature or bug? Has anyone stumbled upon the
same problem? If yes, how to make Facebook really remember the new
"device" logging in?
Thanks.