Resolved Queries based on the Lookup field returning no records

I am designing a simple database using MS Access 2007. One of the fields in the main table is of data type Lookup. The lookup list is in another small table in the database. I have successfully entered data in the main table by selecting the values from the lookup list/table. All queries created based on this Lookup field return no records. I have manually checked and confirmed that there are records that meet the set criteria.