Good afternoon Jennifer,
I ran into this issue when setting up a demo 7.6.1.3 environment today. I'm assuming your database is a SQL server.
Check this link out. https://www.ibm.com/support/pages/node/6615419
It looks like the new version of the JDBC forces encryption and the answer is to add the following to the jdbc entry
;encrypt=false;
P.S. Anyone from IBM reading this it sure would be nice to update the IFIX readme information with crucial information like this when a new issue is found directly related to a fix's with a readme file. It would have saved me some time looking for an answer this afternoon.
Also updated - You can also try this I was able to get my demo environment to connect and this is forcing the sslProtocol and trust the SQL servers certificates. You can see the link below.
https://www.ibm.com/support/pages/node/6953517
;sslProtocol=TLSv1.2;trustServerCertificate=true;