Facebook authentication working on one device but not in another one (in debug apk)

Hi@gabrielmarchesan
If you are trying to distribute the debug build to your some of the customers,the facebook login did not work for them.Because in case of debug build there will be seperate key hash for each of the device.In your case the debug keyhash is already generated and pasted it in your facebook developer console. Thats y the facebook login is working in your device.If you need to work the debug build on your customer device you should collect the keyhash from them.In the present situation the customer got an error screen while login to facebook.The error will be Invalid keyhash error(The keyhash does not match any stored keyhashes).So customer keyhash will shown in the error page.So collect the keyhash from your customer and paste on facebook developer console to fix the login issue.
Please let me know if you have any doubts