Some email clients send bad-formed datetimes, not
parsed by parsedate_tz (both rfc822.py and
email._parseaddr.py). 

The format not recognized is "HH.MM.SS".

I don't know if it's worth taking in account but in
doubt I give a small patch for email._parseaddr :

----------------------------------------------------------------
@@ -90,6 +100,14 @@ def parsedate_tz(data):
         tss = '0'
     elif len(tm) == 3:
         [thh, tmm, tss] = tm
+    elif len(tm) == 1:
+        # Small hack to get HH.MM.ss
+        tm = tm[0].split(".")
+        if len(tm) == 2:
+            [thh, tmm] = tm
+            tss = '0'
+        elif len(tm) == 3:
+            [thh, tmm, tss] = tm
     else:
         return None
----------------------------------------------------------------