This looks a little bit weird to me: a Python "None" value as "name"?
Futher more, to debug this issue you might want to use --debug-challenges, which pauses Certbot at the moment the challenge(s) has/have loaded (i.e.: made the changes to Apache), but before it instructs the ACME server to validate them.
While Certbot is paused, you can try to debug the issue within Apache further.