Getting "Invalid appsecret_proof provided in the API argument" when trying to log on with FB

[exodeveloper]

When trying to log on with FB, i get this:

Error code: 8010
Error message: “Invalid appsecret_proof provided in the API argument”

I use the same code as previously, but now I get this error. There is no problem with the FB login itself, it’s just when I call backendless. I read this thread:

Login with Facebook app results in error "API calls from the server require an appsecret_proof argument"

I have followed the steps described here: https://backendless.com/docs/ios/users_facebook_login.html and have a working Facebook login integration. Recently some of my iOS users reported a problem with Facebook login and upon investigating it I found a curious case. The steps to reproduce it are: Delete Safari cache (Settings > General > iPhone Storage > Safari > Website Data > Remove All Website Data). This is needed in order to simulate first time Facebook login Install Facebook app and lo…

but I do not understand how this became an issue with backendless now when my code has worked this far. What is an appsecret and what does it mean that it is invalid?

[Igor_Bogunkov]

Hi, @exodeveloper!

Facebook’s appsecret is used to decode encrypted messages from Facebook. If you only intend to get it, please reproduce the steps in guide https://backendless.com/docs/android/mgmt_social_settings.html .

appsecret_proof is generated based on the appsecret and Facebook app id, so make sure you use this pair that was generated by corresponding Facebook developer’s app.

[exodeveloper]

Ok, thanks!