Admin upgrade page doesn't load with a CDN

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My environment variables in app.yml:

Custom emoji don't use CDN for S3 stored assets in a few pages

I did have a look at that thread, and as far as I can tell my configuration should be right: DISCOURSE_CDN_URL: https://thrivecommunity-cdn.b-cdn.net DISCOURSE_USE_S3: true DISCOURSE_S3_REGION: eu-central-1 DISCOURSE_S3_ENDPOINT: https://s3.eu-central-1.wasabisys.com DISCOURSE_S3_INSTALL_CORS_RULE: false DISCOURSE_S3_ACCESS_KEY_ID: aaaa DISCOURSE_S3_SECRET_ACCESS_KEY: aaaa DISCOURSE_S3_CDN_URL: https://thrivecommunity-uploads.b-cdn.net DISCOURSE_S3_BUCKET: thrivecommunityforum…

In addition I have the assets upload hook from: Using Object Storage for Uploads (S3 & Clones)