Terrain clamping

Our drone is using JIYI Terrain sensor, whenever flying there is a message in Aerogcs green that says Terrain: clamping Offset -n to n currently i have encounted this all the 3 recent flight done, in first flight TERRAIN_OFS_MAX was decided 10 m then this message pop up Terrain: clamping Offset , then i changed TERRAIN_OFS_MAX to 15 m , i got Terrain clamping: Offset -16 to -10, then i changed the value to 3 m, there was no error but then again flew then error came about to be -7 to 3,

my question is why is this error being shown, and how to resolve this error, what is the correct parameter value for TERRAIN_OFS_MAX and when using JIYI terrain sensor what all parameters are required to be set and what are their values.