I believe there may be some confusion in your question. The theory of relativity was not questioned by Albert Einstein himself, as he was the one who proposed and developed the theory.
Einstein's work on the theory of relativity revolutionized our understanding of space, time, and gravity. He initially introduced the special theory of relativity in 1905, which challenged the classical notions of absolute space and time and introduced the concept of the speed of light as a fundamental constant. Later, in 1915, he formulated the general theory of relativity, which provided a new description of gravity as the curvature of spacetime caused by mass and energy.
While Einstein's theories faced initial skepticism and required rigorous scientific scrutiny, they were ultimately validated through empirical evidence and extensive experimental verification. One of the key pieces of evidence supporting the theory of relativity was the observation of the bending of starlight during a solar eclipse in 1919, which confirmed the predictions of general relativity.
It is worth noting that scientific theories are always subject to questioning and refinement as new evidence, experiments, and observations emerge. However, Einstein's theory of relativity has stood the test of time and has become one of the cornerstones of modern physics, providing a comprehensive framework for understanding the behavior of objects in the universe at both small and large scales.