Cannot start the vertserver with non root user. It says can not read the configuration file.

I cannot start the virt server with appadm user with non root user in Smartbear with which it was running previously. It throws error as shown in below log. But it can be started with root user.

WARNING: All illegal access operations will be denied in a future release
ERROR [2022-06-15 15:57:19,437] com.smartbear.virtserver.VirtServer: Failed to read the configuration file.
ERROR [2022-06-15 15:57:19,445] com.smartbear.virtserver.VirtServer: UNEXPECTED ERROR:
! java.lang.NullPointerException: null
! at com.smartbear.virtserver.VirtServer.a(VirtServer.java:273)
! at com.smartbear.virtserver.VirtServer.<init>(VirtServer.java:232)
! at com.smartbear.virtserver.VirtServer.main(VirtServer.java:166)
ERROR [2022-06-15 15:57:19,445] com.smartbear.virtserver.VirtServer: Could not start the Server, shutting the JVM down
[appad