There is some service parameter in the domain registration service template that is needed to be set "Required" - "Yes"/"No", but an option is not editable:
Why? How to change an option?
The parameter is system, was setup on plugin installation and configuration, therefore cannot be manually edited. If according to the registrar rules an option shall be required and this is a plugin developed by Parallels, please contact Parallels Technical Support Team to confirm a bug in a plugin. If this is a plugin developed by third-party developers, please contact the plugin vendor to get assistance, code changes are required, the plugin is to be updated after issue fixing and recompiling.