The Send Message Event stops working after increasing the number of execution and analytics engines.
The following type of error is observed in the db_PX*.log located in <APPIAN_HOME>/logs/:
<APPIAN_HOME>/logs/
[PX201] {pe0.kdb ,138329} (Default) ERROR .a.noa "Activity ****: 'Send Message', Process ****: 'Process Name', " "type"
This issue has been addressed via AN-113146 in the following Appian hotfixes/versions:
Apply the latest hotfix to your Appian installation or upgrade to the latest version of Appian.
This article applies to Appian 18.2 and 18.3.
Last Reviewed: September 2018