Exactly as smhickel said, or preferably, create a new manager user called "fop2" in manager_custom.conf
Don't change the password for admin in manager.conf, cause this broke your GUI.
Instead open manager_custom.conf, and put this into that file:
[fop2]
secret = your password
deny = 0.0.0.0/0.0.0.0
permit = 127.0.0.1/255.255.255.0
read = all
write = all
writetimeout = 1000
eventfilter=!Event: RTCP*
eventfilter=!Event: VarSet
eventfilter=!Event: Cdr
eventfilter=!Event: DTMF
eventfilter=!Event: AGIExec
eventfilter=!Event: ExtensionStatus
eventfilter=!Event: ChannelUpdate
eventfilter=!Event: ChallengeSent
eventfilter=!Event: SuccessfulAuth
And put this in fop.cfg
[general]
; AMI definitions
manager_host = 127.0.0.1
manager_port = 5038
manager_user = fop2
manager_secret = your password