This has been raised as a defect due to our CtrlDataExport utility not supporting TLS 1.2 - This will be fixed in a future release of TIBCO Nimbus. This affects all releases upto and including V 10.2.x
Workarounds available are as follows:
1. install SQL Server on the same server as TIBCO Nimbus
2. Re-enable TLS 1.0 / 1,1 if this is not possible
3.A further workaround is available here:
https://stackoverflow.com/questions/36452638/dbnetlibconnectionopen-seccreatecredentials-ssl-security-error. (Please note that you follow the steps at this link at your own risk, TIBCO does not guarantee or warrant the advice documented here)