New Phantom II owner - can't connect

[7750000]

Hi!

I've got two Phantom II
once they we connected, but after few days both disappeared from application
I'v tried to reconnect
one pcs connects perfectly as per instruction says
the second one does not goes to connect mode (pink light)
after long press on button it just switches off on 5 second, never reach 7 sec ))
power off, wait, airplane mode, nothing works
both connected via ethernet
both visible via browser

what do I do wrong?

Help
A