BUG: Corrected TypeError message

doc/source/whatsnew/v2.0.0.rst

@@ -1197,6 +1197,7 @@ Timezones
 - Bug in :func:`to_datetime` was failing to parse date strings with timezone name when ``format`` was specified with ``%Z`` (:issue:`49748`)
 - Better error message when passing invalid values to ``ambiguous`` parameter in :meth:`Timestamp.tz_localize` (:issue:`49565`)
 - Bug in string parsing incorrectly allowing a :class:`Timestamp` to be constructed with an invalid timezone, which would raise when trying to print (:issue:`50668`)
+- Corrected TypeError message in :func:`objects_to_datetime64ns` to inform that DatetimeIndex has mixed timezones (:issue:`50974`)
 
 Numeric
 ^^^^^^^

pandas/core/arrays/datetimes.py

@@ -2200,7 +2200,7 @@ def objects_to_datetime64ns(
         #  datetimes but they have conflicting timezones/awareness
         if allow_object:
             return result, tz_parsed
-        raise TypeError(result)
+        raise TypeError("DatetimeIndex has mixed timezones")
     else:  # pragma: no cover
         # GH#23675 this TypeError should never be hit, whereas the TypeError
         #  in the object-dtype branch above is reachable.

pandas/tests/indexes/datetimes/test_constructors.py

@@ -285,6 +285,10 @@ def test_construction_index_with_mixed_timezones(self):
         tm.assert_index_equal(result, exp, exact=True)
         assert not isinstance(result, DatetimeIndex)
 
+        msg = "DatetimeIndex has mixed timezones"
+        with pytest.raises(TypeError, match=msg):
+            DatetimeIndex(["2013-11-02 22:00-05:00", "2013-11-03 22:00-06:00"])
+
         # length = 1
         result = Index([Timestamp("2011-01-01")], name="idx")
         exp = DatetimeIndex([Timestamp("2011-01-01")], name="idx")