SymptomsProvider cannot create reseller account in PCC at Top > Account Director > Reseller Manager, the button 'New Reseller Account' is simply missing on the screen.
CauseThe button 'New Reseller Account' is not shown because Provider does not have free reseller accounts in PBA-S license.
Check current usage of licensed options in PCC at Top > Configuration Director > License Manager > Parallels Business Automation - Standard Licenses.
ResolutionSince PBA-S license accounts only active reseller accounts then two solutions are possible for the problem:
1. Find and deactivate existing reseller account which is not used (if any)
2. Contact Parallels sales representative to adjust number of reseller accounts in PBA-S license