Hi All,
I am stucking while using the oauth plugin for my Piwigo gallery.
I sets up to use the facebook account for login / register actions,
"almost time" I get a pop-up window says " you cannot access this page directly.2 ",
and very rarely it suddenly success. All fields in my Facebook APP sets right, it's confused to "almost time it's not get to work, suddenly success once after you trying again and again", how can I fix this issue ?

Also, does there anyway to merge the two accounts from same mail address automatically ?
For exsample, I registered the gallery from default way, next time I am trying to use the facebook log-in,
it loads my facebook info then required me to input my E-mail, I can not input the same address and it will become two accounts if using a different mail address here.

Any suggesting will be appreciation, thank you.

spec: Piwigo 2.5.1 / Oauth plugin lastest version / stripped theme