Integrated with github error

I tried to integrated with github but meet one error, after authenticated on github, pforum will redirected to invalid URL:

https://pforum.app/login/oauth/access_token/&statekey=WGxHYk9mRmFuV2pXUW01V1dDcy8vdz09?code=8404b678049d45b4e8e5&state=U3hyaExkNU9VdUkxZWtHUjNzUVZUdz09

The page shows:

404 Unfortunately, the page you are requesting can not be found!

My github config is as follows:

'github' => [
    'clientId'     => '0a92e509d******f47e6',
    'clientSecret' => '7ada184973ab4f******39a1574e3a8728723a36',
    'redirectUri'  => 'https://pforum.app/login/oauth/access_token/'
],

I have a workaround: change the code to ignore the statekey, anyone have better idea?