Error while SO Invoice 'The Item Is Not Relevant For Billing'

Hi Colleagues,

I have created a Time and Material Project and when I am trying to Invoice the SO related to particular Project request getting below Error.

Errro Description :-

"The item is not relevant for billing"

Schedule Line Number 0044

Counter in Control Tables 00

Message Identification VF

System Message Number 044

Output Type I

Message Variable 01

Message Variable 02

Message Variable 03

Message Variable 04

Group Type F

Background :-

I created a Project

Entered the time sheet

Run CATS :- Transfer to Project system

Display actual cost line items

Run RRB and created billing request

In the time of Invoicing SO getting error.

I have checked all the configuration but unable to sort out the problem.

Please suggest me if I missed something or need to change the configuration.

Thanks in Advance

Regards

Manoj Bansal