Please identify this error and help me out.
This is not an error.
numpy uses C inside, which has datatypes that can overflow.
In the first case you use variables that are of python types, which have arbitrary precision (limited only by the available memory on the system).
In case of
numpy you have values that have a fixed precision (which limits it’s upper and lower possible value). Calculating dot product for such big numbers results in an overflow, so the number wraps around and starts counting back from the lowest possible value.