Error on preview when username contains Umlaut #1986
Description
A user with a Umlaut in the username can't preview pages and gets the error message
'ascii' codec can't encode character '\xf6' in position 79: ordinal not in range(128)
The locales on the system where we saw the error are all POSIX, not a UTF-8 locale.
With a Unicode locale, all works fine.