When adding a gift code on StubHub, they're case sensitive, which means you need to enter them exactly as they appear (including dashes).
• Add a StubHub gift code on a desktop
2. Enter the gift code number
3. Click Add
• Add a StubHub gift code on the app
2. Tap the + sign
3. Enter the gift code number. Tap Add.
4. Check the code you want to use Apply