using UCC certificates possible?

We have an UCC certificate for our www domain and want to use this in Icewarp 12.0.4, unfortunately we always receive an error when we try to import it. Of course we added mail as alternate DNS.

Error in the log is
SYSTEM          [0B60] 14:55:16 Load SSL verifiy location: PEM_read_bio_X509_AUX failed

So the question is, will this be supported through Icewarp at all?
Where's the error in the process we do?

kind regards

Michael Rantz