Allow CORS origin error when there's a server 500

Causes confusion because it's not the real issue

See django-webidoidc-provider#7 (comment 50762) and energie-partagee/djangoldp_energiepartagee#14

added BUG label

mentioned in issue django-webidoidc-provider#7 (closed)

mentioned in issue energie-partagee/djangoldp_energiepartagee#14

@Marjolaine update on how the Happy Dev variation of this issue was resolved: django-webidoidc-provider#7 (comment 51007)

I don't really get it but I'll synchronise with @balessan tomorrow

changed title from OPTIONS request Allow CORS origin error to Allow CORS origin error when there's a server 500

changed the description

mentioned in issue framework/sib-auth#41 (closed)

mentioned in issue djangoldp-account#80