I entered the ref# and the Watch#, but it's asking for an 'access code' and I don't know where to find that...Not sure if this will work either, but on Omega's website has a way to access your Master Chronometer Certification Info (assuming it is one of recent ) to guarantee authenticity. Try
https://www.omegawatches.com/en-us/masterchronometer
Been looking, very hard to choose and 95% plus of all Omegas are available.