My fingerprint sensor just stopped working, nothing happened previousl

@afhorafolabi first try to reboot your phone to check if your fingerprint sensor is working. IF that does not work you want to check and update your software. Go to Settings==>About Phone==>System Update and let your phone check for any updates. If there are any, those should show up as Download Update. Use those to download and update your Tecno-Spark-8-Pro

You can still clear your cache and other things if the above did not work. Check sites like this one for how to clear your caches etc.

If your fingerprint sensor hardware does not even show up in your settings etc. then it is possible that this is a Tecno firmware issue. You'd have to check with Tecno support or their individual forum for that.

If none of that worked, you may have an actual hardware issue, like a failed fingerprint sensor. Since iFixit does not yet have a guide for that, try something like this video It is not specific to the fingerprint sensor but will at least get you into your phone.

Replacement sensors are readily available at many online stores. Purchase one from a vendor to your liking, just make sure you purchase a fingerprint sensor for your exact model.

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.

Repair is War on Entropy!