updated firmware on nighthawk AC2600 and now locked out of router control forbidden 403

internet was running slow so i signed into router control panel to find firmware needed updating. this was the first time the unit had me put in the SN and the admin sign in just to update firmware. do not know if it updated. the little meter was almost full when the screen changed telling me to sign in as admin and change admin password and security questions , completed that and was redirected to admin sign in page but right as it started to sign in the screen first flashed orange telling me that netgear had revoked my router admin privileges then it flashed again this time a pink screen giving me the error code " 403 forbidden " I can sign in via mobile but not PC