A network-related or instance-specific error occurred while establishing a connection to SQL Server

Our cy has two sites - and on both identical servers and DBases (= same structure)

We developped reports for the first site and want now to use the reports for the second place.

Rebuilding the reports is not an option.

Merge or append tabels in one report seems the best way.

We established connections between the sites and are able to refresch each table individually.

But on a sheduled and automatic refresch we get failures. 

How can we made the distinction in our connection to the two servers?

Txs

Jan