Got multiple values for non null local custom field

Hi,

I get the following error message while saving a MPP from Project Professional to MS Project Server:

Got multiple values for non null local custom field.

I checked the MPP and found that there are fields with same alias as Enterprise field names. However, these fields are at a Task level, whereas the Enterprise fields are at a Project Level.

I would like to know why this is happening and the resolution for this issue. I don't want to delete the local fields.

Any help in this regard will be appreciated.