Virtualized the servers, any custom or modified Crystal reports do not work

We moved our legacy Epicor 10 from a physical machine to virtual. Maintained the 2 separate servers, app and SQL. All is working well, except… reports.
SSRS are fine.
But, any customized Crystal reports, and any Crystal reports as a menu option, no longer work giving the error


If I go to the SQL server, and open Visual Studio, then run any of the Crystal Reports, they work correctly.
If I run a client at the App server, though, it fails. The report is reachable, I figure it has opened the .rpt file because you can see the parameter form. But seems to fail on pulling the data.

Any ideas as to where I’d start to look?
v 10.0.700.2 if relevant.
Thank you