What is the ruling on the prayers of one who smells the odor of feces on his long fingernails after relieving himself, without knowing whether the feces reached his fingernails or not?

Among the characteristics of fitra (innate disposition) is the care for nails through trimming and cleaning. If the fingers are cleaned after istinja (definition)' (washing after relieving oneself) or wudu' (ablution) and only an odor remains, this is pardoned because the odor is difficult to remove, and your prayer is valid. However, if the odor is from remnants of feces under the nails, and the nails are of a normal length that does not prevent water from reaching the skin, then the prayer is valid, and it is recommended to repeat it within the prescribed time. But if the nails are unusually long and dirt accumulates under them, preventing water from reaching the skin, then the wudu' is invalid, the prayer is invalid, and it must be repeated after completing purification.