EAD need additional evidence

We have a lawer filed our case.
Today receive an update on my EAD,

status as follows:

we mailed a notice requesting additional evidence or
information in this case. The notice explains in detail what additional
material is needed. If you have questions about the notice, what is required,
or if 14 days have passed and you have not received the notice, please call the
National Customer Service Center.

what additional evidence do they need? did anybody get this kind of thing before?