Question

java.lang.NoClassDefFoundError: com/pega/pegarules/priv/alert/AlertBuildContext$ParameterPageFilterType
Mutiple java.lang.NoClassDefFoundError: com/pega/pegarules/priv/alert/AlertBuildContext$ParameterPageFilterType exception is present in Prod logs after the server restart (no clear cache).
Env is recently upgraded to 7.3.1 from 7.2.1. What could be the reason and how to resolve this?
***Edited by Moderator: Lochan to update platform capability tags***