Django Makemessages CommandError ASCII Encoding

Question

The locale / django.po file has 7868 lines. Sometimes the makemessages command works, and sometimes it throws this error: its strange because there is always another django.pot line in the error. And don't forget that it sometimes works with the same code, so the code should be fine

manage.py makemessages -l de
CommandError: errors happened while running msguniq
/app/xxx/locale/django.pot:1871: /app/xxx/locale/django.pot: input is not valid in "ASCII" encoding