If the verification is not passed, first check that both the prism and the sample holder are absolutely clean and the sample holder sits tightly on the refractometer tip before a standard liquid is applied. Make sure the standard liquids are in good condition and not past their expiration date. Also, inspect the prism surface, checking that it is flat and shiny without any scratches, digs or deposition on it.
Repeat the verification procedure. If the verification still fails, print out the verification report, send the data to firstname.lastname@example.org or your nearest representative, and wait for further instructions.