I've recently migrated a customer from CRM 2013 to the cloud (dynamics 365) and since then I can only set the scheduled dates on the two custom activities that they use (scheduledstart and scheduledend) in the past. Whenever i set one of the dates in the future I get a 'No active transaction' error. I have turned off all processes, plugins and business rules but the problem still persists.
When I create a new custom activity entity, I do not get the error, neither do I get it on the default activity entities.
A data migration was part of this migration, but that included both these custom activities as well as the default ones.
Does anybody have any idea where to look for?