SSAS TABULAR 2012 connection problems with Power BI service

Good morning to all,
I wanted to lose their help, the truth is that I don't know what else to do.
I tell you that he implemented in a company a board with Power bi connected to a tabular Analysis services 2012 sp1 that is inside a domain, when publishing the report in the cloud, I have established the gateway and the effective user equal to the upn of the AD, on the gateway side, I understand that I already connect, but when I try to enter the report, I get an error that the model cannot be obtained
The account that I use for the gatway is a domain account that is as administrator of the Tabular instance, and with that same account is that of power bi, I have already verified the upn and it is assigning correctly, but it still does not enter.
Now the detail I see is that the domain you have is a 2008 server and the UPN domain name configuration is different from how they enter the network. for example:
UPN: [email protected]
Red: Empresayy \ User1

I understand that in the effective user of my power bi I must point to [email protected], please if someone helps me at least how to debug what is causing it not to connect, thank you very much