Correct Field Type for Cycle Count Serial Number Field?

Summary:

What is the correct format for the Serial Number field when entering the IMEI for serialized items for a cycle count file load?

We received the error "You must enter serial numbers because the item is serial number controlled." after loading the store cycle count file with IMEI type set as "Text"

We received another error "Error in ESS loader job" after loading the IMEI type as "Number".

Thanks in advance,

Yilian