diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py
index 11deffc..332d94b 100644
--- a/Lib/test/datetimetester.py
+++ b/Lib/test/datetimetester.py
@@ -1979,7 +1979,16 @@
                 seconds = tzseconds
             hours, minutes = divmod(seconds//60, 60)
             dtstr = "{}{:02d}{:02d} {}".format(sign, hours, minutes, tzname)
-            dt = strptime(dtstr, "%z %Z")
+            try:
+                dt = strptime(dtstr, "%z %Z")
+            except ValueError:
+                import os
+                self.fail(
+                    "Issue #25168 strptime() failure info:\n"
+                    f"_TimeRE_cache['Z']={_strptime._TimeRE_cache['Z']!r}\n"
+                    f"TZ={os.environ.get('TZ')!r}, or {os.getenv('TZ')!r} via getenv()\n"
+                    f"_regex_cache={_strptime._regex_cache!r}\n"
+                )
             self.assertEqual(dt.utcoffset(), timedelta(seconds=tzseconds))
             self.assertEqual(dt.tzname(), tzname)
         # Can produce inconsistent datetime