You are not required to have a verification code on your W-2. If box 9 is empty, that is OK with the IRS, and it should e-file.
In some rare cases, an auto-import of a W-2 may fail and put garbage in some of the fields in the W-2. If you are receiving messages about entering a verification code, yet box 9 is empty on the W-2, if you auto-imported the W-2,
please copy down all the information on the W-2 (if you don't have a printed copy), delete the W-2, and add it manually (i.e., when asked for the employer's EIN, just Continue to the next screen where you will enter all the W-2 information at once).