It is an old issue. Try testing it via same members app diagnostics. Try to soft reset phone (only settings reset) and if nothing works, go get checked it out at Samsung service centre before warranty goes out. Some users are saying that Samsung service centre employee told them that an update "cooked" the sensor and repair cost is 3000-4000. If that's true, document everything, file complaint against Samsung for faulty update, resulting in hundreds of devices being out of fingerprint sensor. Also search in community the term A16 Fingerprint and contact users to join your complain who are also facing the same issue.
