Bad response from token request after team creation auth

Hi @jwilander,

Thanks for taking the time to answer me.

I can see with Firefox developper tools a POST request to http://gitlab.mydomain.com/oauth/authorize resulting in a 302 Found response after authentification on gitlab, but nothing in mattermost log (see below)

utf8=✓
authenticity_token=vt72DvWjnXzLESh+3MGs2XPAOr3UzuI1Yvc+PP+zZzWw6wBElqbHlAExAK3KN4z+eScG+hF2DKXfQ/yyNJgU8Q==
client_id=9d4021472038fffa615fa757550879e39dd7e50dd4c86d72bdb39c7c2ed8f334
redirect_uri=http://mattermost.mydomain.com/signup/gitlab/complete
state=eyJhY3Rpb24iOiJzaWdudXAiLCJoYXNoIjoiJDJhJDEwJHRETlA0SFZqdTh4ZlphVXh4a2pVUU94cms2VEp6OS5yZEQ5Mi5id1gwaHBid1h4ZlEySWwyIiwidGVhbSI6ImFsaWNld29yazAxMjM0NTY3ODkxMDExMTIxMzE0MTUxNjE3MTgxOTIwMjEyMjIzMjQyNTI2MjcifQ==
response_type=code
scope=api

Here's my mattermost log :

[2016/02/26 14:35:19 CET] [DEBG] /
[2016/02/26 14:35:27 CET] [DEBG] /api/v1/teams/create_with_sso/gitlab
[2016/02/26 14:35:27 CET] [DEBG] /alicework01234567891011121314151617181920212223242526/signup/gitlab
[2016/02/26 14:35:31 CET] [DEBG] /signup/gitlab/complete
[2016/02/26 14:35:31 CET] [EROR] /signup/gitlab/complete:AuthorizeOAuthUser code=500 rid=4b6e4jy85jyctkrezkx51sckqo uid= ip=78.249.179.124 Bad response from token request [details: ]