This happens when I open a page of Held Messages containing an offending message. I get Server Error (500) in Postorius. Here is the mailman.log:
Sep 07 15:25:39 2018 (32) REST request handler error: Traceback (most recent call last): File "/usr/local/lib/python3.6/wsgiref/handlers.py", line 137, in run self.result = application(self.environ, self.start_response) File "/usr/local/lib/python3.6/site-packages/mailman/database/transaction.py", line 50, in wrapper rtn = function(*args, **kws) File "/usr/local/lib/python3.6/site-packages/mailman/rest/wsgiapp.py", line 214, in __call__ return super().__call__(environ, start_response) File "/usr/local/lib/python3.6/site-packages/falcon/api.py", line 244, in __call__ responder(req, resp, **params) File "/usr/local/lib/python3.6/site-packages/mailman/rest/post_moderation.py", line 160, in on_get resource = self._make_collection(request) File "/usr/local/lib/python3.6/site-packages/mailman/rest/helpers.py", line 159, in _make_collection for resource in collection] File "/usr/local/lib/python3.6/site-packages/mailman/rest/helpers.py", line 159, in <listcomp> for resource in collection] File "/usr/local/lib/python3.6/site-packages/mailman/rest/post_moderation.py", line 150, in _resource_as_dict resource = self._make_resource(request.id) File "/usr/local/lib/python3.6/site-packages/mailman/rest/post_moderation.py", line 77, in _make_resource resource['msg'] = msg.as_string() File "/usr/local/lib/python3.6/site-packages/mailman/email/message.py", line 54, in as_string value = email.message.Message.as_string(self) File "/usr/local/lib/python3.6/email/message.py", line 158, in as_string g.flatten(self, unixfrom=unixfrom) File "/usr/local/lib/python3.6/email/generator.py", line 116, in flatten self._write(msg) File "/usr/local/lib/python3.6/email/generator.py", line 181, in _write self._dispatch(msg) File "/usr/local/lib/python3.6/email/generator.py", line 214, in _dispatch meth(msg) File "/usr/local/lib/python3.6/email/generator.py", line 243, in _handle_text msg.set_payload(payload, charset) File "/usr/local/lib/python3.6/email/message.py", line 315, in set_payload payload = payload.encode(charset.output_charset) LookupError: unknown encoding: _iso-2022-jp$esc