If you are having issues with mag encoding failing or a mag verification error try different cards first, then run a magnetic self test from your printer. This is for “Hi Co” cards only.
Remove the Print Ribbon
Turn the printer off/Hold down the Pause button while turning on the power. Continue to hold down the Pause button for a two to 4 seconds.
A test card with sample magnetic data will be encoded and ejected.
Open notepad and verify with an external mag reader.