Unknown method used in expression:

[nullpointer]

I have this error after the migration from activiti 5 to 6, and I checked the spring logs and all the services are initialized in the Springcontext

Caused by: org.activiti5.engine.ActivitiException: Unknown method used in expression: #{elCorService.makePlat(corWorkflowService.buildContext(execution))}
    at org.activiti5.engine.impl.el.JuelExpression.getValue(JuelExpression.java:56)
    at org.activiti5.engine.impl.bpmn.behavior.ServiceTaskExpressionActivityBehavior.execute(ServiceTaskExpressionActivityBehavior.java:71)
    ... 199 more

[chyder]

Answered here: https://stackoverflow.com/questions/66764831/unknown-method-used-in-expression-in-activiti-6