Issue Getting 500 - Internal server error on Plesk Panel

[nandansinha]

Hi,

When I tried to repair Plesk Installation, it's throw a error message -

Unable to execute "C:\Program Files (x86)\Plesk\admin\bin\websrvmng.exe" --configure-plesk-website:
The parameter is incorrect. (Error code 87) at Unable to add the member (IIS AppPool\PleskControlPanel) to the group (psaadm_users)
at (UserManagement::LocalGroup::addMember line 77)
at addMember(psaadm_users, IIS AppPool\PleskControlPanel)(UserManagement::LocalGroup::addMember line 80)
at _configurePleskSiteAppPool()(PleskWebSite::_configurePleskSiteAppPool line 58)
at configurePleskSite()(PleskWebSite::configurePleskSite line 406)
at Unable to execute console command: '--configure-plesk-website'(vconsoleapp::start line 95)
at Unable to execute command: '"C:\Program Files (x86)\Plesk\admin\bin64\websrvmng.exe" --configure-plesk-website'(vconsoleapp::run line 117)

Please suggest, how to fix it.