Successful login in local but not another servers, everything same

I have a asp.net application which a user needs to log in first. It works perfect when I run it on my local. Same code, same web.config, same database with same user and data, I am running in another server, it gives me:

"Oops! It looks like an unknown error occurred. Please try again and if this issue persists, contact the administrator."

When I try to "reset password", in my local it works but in the other server it says:

Whoops! Invalid email address.

Site in IIS uses ApplicationPoolIdentity in both server. What might cause the issue I could not find anything. Any idea or help would be appreciated.

Thanks.