Cannot create account on WHMCS SolusIO landing page with post-paid module:
SVM_ERROR: Invalid user id provided
New WHMCS installation, there is no clients in it
There are should be at least 1 client created in WHMCS
Due to WHMCS core functionality, SolusIO module does currently require at least 1 client to be present.
- Access WHMCS admin area
- Add at least 1 client - https://help.whmcs.com/m/installation/l/682009-manually-adding-a-client