index 5533 is out of bounds for axis 0 with size 5533

[ven1996]

I am getting an error in the program to get the best symmetric matches.
My first catalog contains ~20,000 rows and the second row contains 5533 rows.

in symmetric_match_sky_coords(ra1, dec1, ra2, dec2, tolerance)
51 # not sure this condition covers all of the possible corner cases. But good enough.
52 # (NB: should put in an assertion to check that tolerance is an angular unit)
---> 53 if sep2d_1to2[i] < tolerance and i == closest_2to1[closest_1to2[i]]:
54 index1_matched.append(i)
55 index2_matched.append(closest_2to1[i])

~/anaconda3/lib/python3.8/site-packages/astropy/units/quantity.py in getitem(self, key)
1043 def getitem(self, key):
1044 try:
-> 1045 out = super().getitem(key)
1046 except IndexError:
1047 # We want zero-dimensional Quantity objects to behave like scalars,

IndexError: index 5533 is out of bounds for axis 0 with size 5533