While Singapore’s Pre-Departure Test (PDT) and Vaccination HealthCerts are considered equivalent to the EU DCC, your destination may be using reader applications that are unable to validate the offline QR codes. You can ask the authorities/businesses if verification can also be done by scanning the online QR code with a mobile device connected to the internet.
Before travelling overseas, we recommend that you check that your offline QR codes can be validated by the reader apps used at your destination if this is required (e.g. such as by testing the code with the relevant reader app), and refer to Safe Travel website for the latest information and advisories for your destination.
Note: You are recommended to regenerate your Vaccination HealthCert if your offline QR codes cannot be verified (or if your certificate does not currently display offline QR codes). This could happen due to updates in EU DCC's regulations which may not be reflected in an older version of the certificate.
If you have recently taken additional COVID-19 vaccine dose(s) or changed your passport number, do regenerate your HealthCert to reflect these updates too before your next trip.