Interaction record and email item

Hi

When I select an email workitem from my inbox and click interact an Interaction is created .

However.....

I get the error message Category INT is not permitted for transaction type ZIR0 and the channel field which I have set as default E-mail - category 401 is blank.

I'm sure this is a config error but have repeatedly checked config.

Everything else on the IR is correct - the email details are in the notes, the subject is in the description.

Any help would be great.

Thanks

PM