Yes, in fact it is a very valid reason. When a bank or mortgage company lends someone money, they do so based on the veracity of the information provided to them. If the lender’s guidelines say that someone has to have a two-year job history, then the lender may ask for proof of that two-job history.
Furthermore, they can (based on the document called “ Borrower Authorization” that they have people sign), double check the veracity of the information given to them by a borrower. So, if someone says on their application that they’ve worked for Acme Widgets for the last two years and the lender calls up Acme Widgets, who tells them “John Doe?? Who’s that? We’ve never had an employee by that name,” the lender would conclude that they are unable to verify the information and deny the loan.
Believe it or not, banks and mortgage companies want to approve as many applications as they can, so long as it is financially prudent for them to do so. If I were you, I would talk to the loan officer who handled your application and find out what information, in particular, they were not able to verify. Once you have that figured out, enlist the help of a good mortgage broker who will be able to help you get the loan you are looking for.