Indeed, the recently published Einstein correspondence from the period
1914 to 1918 makes abundantly clear the importance of Einstein's
contacts with Tullio Levi-Civita, Hermann Weyl, Felix Klein, Emmy
Noether, and a number of other mathematicians.

Many of these mathematicians that Einstein sought for help with his
theory thought that Einstein was an incredible dullard when it came to
mathematics. David Hilbert said, “Every boy in the streets of
Gottingen understands more about four–dimensional geometry than
Einstein.” Minkowski (Einstein’s math professor) thought that
Einstein’s mathematical abilities were appalling. Einstein himself is
on record whining about the difficulty he had in understanding
Minkowski’s famous Cologne lecture of 1908 on the unification of space
and time.