'net/pop' library (POP3/APOP client) has a bug: Authentication fails
if username or password contain %-sign. The library uses:
  ...get_response('USER ' + account)
    ... sprintf(fmt, *fargs)
Percent sign '%' in a username/password are interpreted by sprintf()
as format specifiers.

The fix is in POP3Command.auth() line#793. Instead of

        check_response_auth(get_response('USER ' + account))
        get_response('PASS ' + password)

use

        check_response_auth(get_response('USER %s', account))
        get_response('PASS %s', password)


Regards,
-- 
-Laza
    http://lazax.com/blog/