Your output encoding is not UTF-8, there may be issues with the software when anything is printed to the terminal or log files

edit

In this case your python output encoding for stdout and stderr streams is not "utf-8". The message gives you a warning as whenever a non-ascii message is logged or printed to the standard output there will be an exception.

For example - statements like logging.debug('....') may cause 500 errors in this situation.

One solution to this is to have logging.debug('....').encode('utf-8')) everywhere - to make sure that you print just bytes, but this would be too tedious. Another - set the output encoding to 'utf-8' at run time.