--- a/python/mozbuild/mozbuild/mach_commands.py
+++ b/python/mozbuild/mozbuild/mach_commands.py
@@ -1929,24 +1929,24 @@ class PackageFrontend(MachCommandBase):
             for attempt, _ in enumerate(redo.retrier(attempts=retry+1,
                                                      sleeptime=60)):
                 try:
                     record.fetch_with(cache)
                 except (requests.exceptions.HTTPError,
                         requests.exceptions.ChunkedEncodingError,
                         requests.exceptions.ConnectionError) as e:
 
-                    if isinstance(e, requests.exceptions.ConnectionError):
-                        should_retry = True
-                    else:
+                    if isinstance(e, requests.exceptions.HTTPError):
                         # The relengapi proxy likes to return error 400 bad request
                         # which seems improbably to be due to our (simple) GET
                         # being borked.
                         status = e.response.status_code
                         should_retry = status >= 500 or status == 400
+                    else:
+                        should_retry = True
 
                     if should_retry or attempt < retry:
                         level = logging.WARN
                     else:
                         level = logging.ERROR
                     # e.message is not always a string, so convert it first.
                     self.log(level, 'artifact', {}, str(e.message))
                     if not should_retry: