Hi Jainee Even I faced the same issue, I checked the entire flow once again, then i realized my mistake that in Content Modifier Step UndeMessage Header Tab, in Data Type field I entered java.lan.String, where I missed g (correct data type: java.lang...

Hi Charlie_LinFirst you need to assign role collections 1) APIManagement.SelfService.Administrator and 2) APIPortal.AdministratorFor this you need to go to security(in btp cockpit)->Users(select your user)->Click on Roll Collections->Assign Roll Coll...