After an upgrade or site restart, process models fail to save with the following error:
Non-nullable input ACP(s) for unattended node(s) must not be null: isAsynchronous
Users may also see *.l files generated in the <APPIAN_HOME>/logs directory after the upgrade or site restart. More information about these log files can be found here.
<APPIAN_HOME>/logs
The application server is in an inconsistent state due to an engine issue, usually an engine roll back or disconnect.
Follow KB-1232 to restart the application server and clear application server cache.
Open a support case with Appian Support to coordinate an application server restart for the environment.
This article applies to all versions of Appian.
Last Reviewed: June 2021