Database Mirroring error, but everything looks OK I'm setting up a Mirroring study session in separated servers.

Everything looks ok, the firewall in my machine is disabled and in the another server it has an inbound\outbound rule to accept port 5022.

I could check that both endpoints are created and STARTED in both servers
with SELECT * FROM sys.database_mirroring_endpoints.



I tried with both configurations, by using services account, and leaving them blank. 

I checked with port query that the server is listening on this ports:



What more can I check?



The reason I'm asking this question is because I read every other question about mirroring here, but none of them could help me.



In a post, I read that someone fixed the error with:


  Go to services.msc and check the sql server is running under which
  account. Make sure that sql server and sql server agent services
  should run with same credentials.


But I use different credentials for AGENT and SQL SERVER.

Is this a problem? I've never seen this before.



EDIT2:

I could fix this error ( it still shows me this error, but if I run the mirror again, it shows me error 1431.)

Using ALTER DATABASE [Database_Name] SET PARTNER OFF didn't solve the problem. it just restart the task, and errors and errors again.
Have you granted the CONNECT permission to the Mirroring Endpoint for the SQL Server service account?

GRANT CONNECT on ENDPOINT::Mirroring_Endpoint TO [domain\user];