It means the moodle microservice cant reach the jail microservice. It would has been happening by a wrong configuration of your Jail microservice. If you already reviewed the jail configuration, it would has been pasing by a SSL/TSL problem. Please review your certificates of your microservices ecosystem.
Please review the configuration var called REACT_APP_CLIENT_ID, you need allow the acces for yor app client id in google project. More info
4. I get "VPLPluPlusCore.Exceptions.NoTestsFound: No tests found" However i ensured those files exist
If you modified the vpl test classes, let ensure the test classes has the appropiate annotations for vpl . Also, you can download the moodle activity, restore it and copy-paste the vpl test classes. Also, This issue should happened because you need to keep the .java files at execution time. See "Files to keep when running" in vpl activity options