Executing a simple Powershell command using SQL job

I am trying to delete sql backup files under UNC path from one server to another server. I am getting an error message - An object at the specified path \\PRPWD01V0131\L$\SQLBackup\Archive does not existScript -remove-item "\\PRPWD01V0131\L$\SQLBackup\Archive\*" -include *.bak -recurseI believe it's UNC path issue with credentials. Any help is appreciated!!Thanks!