[imp] Message not displayed with IMP H3 4.0.2

[lst_hoe01 at kwsoft.de]

Hello

in our testing installation a message lead to a blank page with IMP H3 and no
error found in the logs. The same message on the same server is displayed fine
with IMP 3.2.6.
It is a S/MIME signed message and no S/MIME support is configured in IMP H3.

Any hints where to dig?

Thanxs

Andreas