I am sure anyone working with planning and production module of D365 must have seen this message.
"Production order could not be scheduled. Not enough capacity found."
This message is too generic at the moment and often leaves user with no clue about what is the root cause for the same.
At the moment user need to do a lengthy manual check up for all the possible reasons - like check if there are applicable resource are found or not, if there calendar has a working time defined or not, check for the route group settings etc.
It would be helpful if system specify the reason why it could not be scheduled and that will save a lot of for the planner and production.