Hello,
I knew Service activity has problem with Firefox, please pay attention to my description.
I have CRM 365(v9.0.11.9), I created a service and added some resources, then I created a service activity with that service and scheduled it. There is no problem, but when I wanted to open service activity and edited it I got some errors:
1- One of my resources disappered and not show in the list.
2- after I choose my resources again, I can't save it and CRM says:(Microsoft Dynamics 365 cannot determine the correct selection rule for one or more of the selected resources. Reselect the resource from the selection rule in the Form Assistant.) ...Althought I don't get this error in Chrome or Opera!