Was this the only igniter of its type (brand and model) you used? If your controller can light other igniters of this type, then it’s not the controller, it’s the igniter. On the other hand, if your controller can‘t light any igniters of this type, then it’s the controller.
The fact your controller can light some kinds of igniters doesn’t mean it can light all kinds of igniters, even if the igniters are perfectly fine. My first composite motors I flew on my own launch equipment were Aerotech E20s that came with First Fire Jr igniters, and my Estes E controller would not light those. I had to use Estes PSII igniters for those E20s when I used my own controller. But the First Fire Jr igniters that would not work with my equipment were actually perfectly fine, and I used those at club launches on their big 12-volt equipment.
Also, just because you get a continuity light, does not mean the igniter is good. Even if there are no shorts on your leads and setup (clips not touching, etc.) the igniter can have an internal short you cannot always see. If there is a bridge wire or chip covered in pyrogen, you might never see that there is a short between the lead wires underneath the pyrogen. Some kind of manufacturing defect with stray solder or something similar bypasses the bridge wire under the pyrogen, and you never see it. Even though it looks good, and the continuity light comes on, it’s never going to light. Toss it out, and use another.