Unable to create FTP account in Plesk: Error: Cannot add duplicate collection entry of type 'site' with unique key attributes 'name, id' respectively

Symptoms

• Adding a new FTP account at Domainss > example.com > FTP Access > Add an FTP Account fails with the following error:

  PLESK_ERROR: Error: ftpmng failed: Filename:
  Error: Cannot add duplicate collection entry of type 'site' with unique key attributes 'name, id' respectively set to '203.0.113.2, 28',br/>
  In module Exception type: System.Runtime.InteropServices.COMException at Microsoft.Web.Administration.Interop.IAppHostElementCollection.AddElement(IAppHostElement pElement, Int32 cPosition)
  at Microsoft.Web.Administration.ConfigurationElementCollectionBase`1.Add(T element)
  at Microsoft.Web.Administration.SiteCollection.Add(String name, String bindingProtocol, String bindingInformation, String physicalPath, Byte[] certificateHash)
  at IISFtpSites.add(IISFtpSites* , basic_string,std::allocator >* idnName, basic_string,std::allocator >* protocol, basic_string,std::allocator >* bindings, basic_string,std::allocator >* sPhysicalPath)
  at addServer(203.0.113.2)(IIsFtp7ServerAdapter::addServer line 694) at updateFtp(203.0.113.2)(FtpServerManager::updateFtp line 378) at reconfFtpUser(user)(FtpServerManager::reconfFtpUser line 471) at updateUser(user)(FtpServerManager::updateUser line 144) at execute console command --update-user(vconsoleapp::start line 100) at execute "C:\Program Files\Parallels\Plesk\admin\bin\ftpmng.exe" --update-user "--ip-addresses=203.0.113.2" "--login=user" "--home=C:/Inetpub/vhosts/example.com" "--quota=0" "--permissions=3"(vconsoleapp::run line 117) (Error code 1)

• plesk repair ftp utility shows an error regarding the IP address:

  C:\> plesk repair ftp
  Checking FTP home junctions ftpmng failed: Site 203.0.113.2 doesn't exist at (FtpServerManager::getServerBaseDir line 639) at execute console command --get-server-base-dir(vconsoleapp::start line 100) at execute "C:\Program Files\Parallels\Plesk\admin\bin\ftpmng.exe" --get-server-base-dir "--ip-address=203.0.113.2"(vconsoleapp::run line 117) (Error code 1)

• IIS > Hostname > Sites > 203.0.113.2 has no localuser and logs folders.

Cause

203.0.113.2 website in IIS contains another application.

Resolution

1. Connect to the server via RDP.

2. Go to IIS > Hostname > Sites.

3. Rename 203.0.113.2 website in IIS.

4. Recreate FTP website:

   C:\> "%plesk_dir%\admin\bin64\ftpmng.exe" --add-ip-address --ip-address=203.0.113.2

   Note: Substitute 203.0.113.2 with the actual IP address:

5. Repair FTP:

   C:\> plesk repair ftp