Trying to forward an email causes eM to crash


eM has been working fine, but now, whenever I try to forward a received email, eM crashes back to the desktop.

The first part of the error code I find is this:

eM Client (7.1.30794.0)
Windows: Microsoft Windows NT 10.0.16299.0, Framework: 4.0.30319.42000
The following error has occurred:
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. —> System.ArgumentException: Prefix “xmlns” is reserved for use by XML.

Any ideas??