@westjan I would try to update end date to a more manageable year, 2049 for example. I guess year 3333 could throw IFS off. 

How many Resources are in the source Work Center? I got the same message when copying a WC with more than one resource, regardless if there was or was not an End Date on the Cost Sets.

Recall the only objects in a WC with an end date are costs, resources, and RRP scenarios.

Hi, 

only one, but I am not able to enter the “End date”. That is the problem then.

Hi I have tried it even with normal date 31.12.2024.

Error is the same.

An end date should not be required for anything in the source work center. Since you receive this error when entering a date tells me it could be a bug. What can you find from the debug console?

Hi, debug here:

@westjan the information from the debug console would need examined by someone with a technical background to find why it is failing, i.e., what is being called in the api. You may also consider submitting a case to IFS to determine if this is a bug.