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Home > Success Center > Patch Manager > WSUS synchronization fails with HTTP Error 503

WSUS synchronization fails with HTTP Error 503

Created by Leif Amland, last modified by Ezgi Muderrisoglu on Dec 13, 2016

Views: 4,620 Votes: 1 Revisions: 13


When initializing an update task with WSUS, the following error is received:


HTTP Error 503. The service is unavailable" 


Patch Manager


There are two possible causes of this error:

  • The WsusPool Application Pool in IIS is in a Stopped state. 
  • The Private Memory Limit (KB) for the Application Pool is set to the default value of 1843200 KB.


Warning: Consult your System Administrator before performing the following procedure. 

  1. Open the IIS Manager.
  2. Expand your site to find Application Pools.
  3. Select WsusPool in the center pane, and then click Start in the Actions pane.
  4. Increase the Private Memory Limit to 4GB (4000000 KB). 
    1. Stop the Patch Manager services.
    2. Select WsusPool in the center pane and then click Advanced Settings under Edit Application Pool.
    3. Manually set the Private Memory Limit to 4GB (4000000 KB).
  5. Restart the Application Pool.
  6. Start the Patch Manager services. [Note: For Patch Manager this is the Eminentware Data Grid Server Service]




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