In WHMCS after marking OpenVZ VPS Invoice as "Paid", WHMCS initiated provisioning of the VPS on the OpenVZ server with HyperVM control panel..

The resilt is blank page with error:

Module Command Error
You must provide login credentials
When i check invoice then, it is really marked as Paid and also the service appears to be provisioned because in WHMCS, VPS got IP, name and service in WHMCS appears like "Active".

So not sure why it returned that error, WHMCS / Utilities / Logs / Module Log dont show any errror.

I would try disabling SSL access in WHMCS / Setup / Products / Servers / serverhere /
Also in HyperVM / Server / Information, checking hostname, etc.