Wiki says that his transfinite numbers met opposition:
Henri Poincaré referred to his ideas as a "grave disease" infecting the discipline of mathematics, and Leopold Kronecker's public opposition and personal attacks included describing Cantor as a "scientific charlatan", a "renegade" and a "corrupter of youth". Kronecker objected to Cantor's proofs that the algebraic numbers are countable, and that the transcendental numbers are uncountable, results now included in a standard mathematics curriculum. Writing decades after Cantor's death, Wittgenstein lamented that mathematics is "ridden through and through with the pernicious idioms of set theory", which he dismissed as "utter nonsense" that is "laughable" and "wrong"
Some Christian theologians (particularly neo-Scholastics) saw Cantor's work as a challenge to the uniqueness of the absolute infinity in the nature of God – on one occasion equating the theory of transfinite numbers with pantheism
Can you briefly explain when the commotion started, if it regarded also his work on number or set theory , show what was the most grounded or shared criticism and when the opposition ended and who turned the tide? Was it Hilbert ? Could you please specify if any doubt is still surviving on any aspect of his theories?
this is definitely not a duplicate of the linked question nor the links in the comments provide any help:
That question tackle a rather marginal problem: whether Poincaré said it or not. I asked what other ideas met opposition an when/ by the help of whom criticism was overcome and, indeed, if it has definitely or if even today there are some detractors.