If this was my device i'd first try to ckear tbe system cache which is achieve by turning it Off and follow a set of button pressess.
Then if no resolution try a Hard Reset which is normally achieved by turning the device Off and follow a set of button pressess. Google should show you what they are.
The downside is this process will more than likely delete your info in it.
That or look to get a diagnostic run on it via a Samsung service location or Samsung Experience.
Current Phone ~ S8 Model: SM-G950F. CsC:BTU.
Samsung Gear s3 Frontier Watch