How to Signup / Login
You can login to ExtrmSport subdomains using same credentials.
For app.extrmsport.com
Click on Login
Click on OpenID Connect
Click on Continue
If you already signup, enter your credential. Otherwise, click on Register
Fill up the form and click Register
Check your email and click on confirmation.
For community.extrmsport.com
Click on Sign Up or Log In.
You will be redirected to the same signup / login pages as above.