The portal structure is:

 

and subportal

 

I registered an user for the subportal and log in with that user. When I tried to Chat I received "Login failed. Can't find account information".

Then I registered the same user in the portal and log in with that user in the suportal (user already created) and the Chat worked OK, using the account information.

 

I use DNN 2.1.2 and I know every portal or subportal have a diferent ID in the database. I think you use the domain name to get the portal ID to find users.

 

Thanks.

 

Juan