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Logfile error: RequestorLockException when connecting to PDN



Errors - doWithRequestorOrThreadLocked error and RequestorLockException are periodically generated in the log file. Errors with "Connection to refused" are also observed.

Error Messages doWithRequestorOrThreadLocked could not obtain requestor instance from H1234567890ABCDEF
~~~ Unable to synchronize on requestor within H1234567890ABCDEF 120 seconds
~~~ Caught unhandled exception: com.pega.apache.http.conn.HttpHostConnectException: Connection to refused
CAUSED BY: Caused by: Connection timed out

Steps to Reproduce

Not Applicable

Root Cause

A defect or configuration issue in the operating environment.  The server in question is behind a firewall.  Each requestorLockException generates a thread dump and indicates the thread that is locked. The thread locked in this case is waiting for a response from a Connect-REST to the PDN, but is not receiving a response (including an HTTP response halting the connection) due to firewall configuration.
Any system behind a firewall should be configured not to make external connections in this manner.


Perform the following local-change: 

Alter the dynamic system setting, AllowAccessToExternalSystem, which determines whether the Pega 7 platform instance attempts to access the PDN.
​The default value is "true". A value of false will configure Pega to not attempt this connection, and therefore the connection does not time out and create errors in the logfile.

Published January 31, 2016 - Updated October 8, 2020

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