I checked and found in db server that microsoft sql server 2012 native client is installed .
The current scenario is that we have already upgraded our APP and DB server from 2008 to 2016.
In 2016 TLS 1.2 is enabled but while instaling DNA Fusion 7.5 or 7.7 in app server it is asking the DBinstance name and upon providing the DB instance when you are trying to test the connection it is showing error that connection failed:invalid connection string attribute.
But the same installer file when I am trying from 2008 server where SSL is enabled instead of TLS it is working as expected.
I have already checked with our server team and according to them server is built with correct configuration hence there is no issue at server end.
Is SQL Server Native Client 11.0 is required instead of microsoft sql server 2012 native client