Scenario:
I set up successfully TFS2010 webdeploy task for solution. Everything worked fine until suddendly something went wrong in the deployment task.
Solu
All you have to do is re-run the script "AddDelegationRules.ps1" located in "C:\Program Files\IIS\Microsoft Web Deploy V3\Scripts\"
This is the script that is run when web deploy is first installed. It will re-create any missing delegations, re-set the passwords for both WebDeployAdmin and WebDeployConfigWriter, and add WebDeployAdmin back to the Administrators group.
You would still need to set the password on each account not to expire after re-running the script.