I have free test salesforce

this trail
https://trailhead.salesforce.com/modules/apex_patterns_dsl/units/apex_patterns_dsl_apply_dl_principles

i shell deploy the source librarys
https://githubsfdeploy.herokuapp.com/?owner=financialforcedev&repo=fflib-apex-mocks
https://githubsfdeploy.herokuapp.com/?owner=financialforcedev&repo=fflib-apex-common

if i go Sandbox.. i cannot log in.. if i go production i get "OAuth Error"
We can't authorize you because of an OAuth error. For more information, contact your Salesforce administrator.
1800 : There was a problem in setting up your remote access