Error dropped

error trace : 2023-02-10 10:17:19.573 ERROR 9208 --- [oundedElastic-3] reactor.core.publisher.Operators : Operator called default onErrorDropped

reactor.core.Exceptions$ErrorCallbackNotImplemented: java.lang.IllegalStateException: Cannot access state in VaadinSession or UI without locking the session.
Caused by: java.lang.IllegalStateException: Cannot access state in VaadinSession or UI without locking the session.
at com.vaadin.flow.server.VaadinSession.checkHasLock(VaadinSession.java:578) ~[flow-server-