That was the perfect hint. My “Order endpoint” was named “order” (this worked since 2016). When I leave the setting “Order endpoint” empty or use another slug than “order” everything works like it should.
Thanks for your help!
I did this and it is set correctly. I never changed the settings anyway as Sunshine was running smoothly until the recent update.
Any other ideas?
No, I didn’t update the theme. It’s the same version than before with which Sunshine Photo Cart worked over the years.
I also checked everything with the Twenty Nineteen theme and get the same error there too.
