Notifying Fallback Contacts dont work

Hello all,

i have upgraded my Check_MK from Version 1.6.0p13.cre to 2.0.0p3.cre and so far its working fine but i found one strange problem that i cant explain. Befor the Update the notification to the fallback contact was working fine but after the update i get the following error in the var/log/notify.log

2021-05-04 10:39:19,642 [40] [cmk.base.notify] ERROR:
Traceback (most recent call last):
File “/omd/sites/mysite/lib/python3/cmk/base/notify.py”, line 355, in locally_deliver_raw_context
return notify_rulebased(raw_context, analyse=analyse)
File “/omd/sites/mysite/lib/python3/cmk/base/notify.py”, line 487, in notify_rulebased
plugin_info = _process_notifications(raw_context, notifications, num_rule_matches, analyse)
File “/omd/sites/mysite/lib/python3/cmk/base/notify.py”, line 595, in _process_notifications
notify_via_email(plugin_context)
File “/omd/sites/mysite/lib/python3/cmk/base/notify.py”, line 1369, in notify_via_email
for encoding in os.popen(“locale -a 2>/dev/null”):
File “/omd/sites/mysite/lib/python3.8/codecs.py”, line 322, in decode
(result, consumed) = self._buffer_decode(data, self.errors, final)
UnicodeDecodeError: ‘utf-8’ codec can’t decode byte 0xe5 in position 1079: invalid continuation byte

Did someone experinced something simmilar?

Have nice day.