Zoom shows chat notification but there is no message to display

Hi there, 

since one week I´ve got the strange symptom, that zoom (version  5.13.3 (11494)) shows that there should be 3 new messages. If I open Zoom, it is shown in the Team-chat area. 

I happens on every device I´m loggin on (3 workstations, 1 Mobile device), I´ve got no new message left, no contact requests.

Anyone else who has/had this and knows a solution??

Thanks in advance

Frank