Dear original poster, have you perchance tested with Cloudflare as a front-end proxy? It appears that the moment one activates the orange cloud icon, the site becomes inaccessible, presenting naught but a blank page.
The final conundrum I encountered was that the utilisation of Cloudflare resulted in a file upload limitation of 100MB. Should one wish to surpass this threshold, it becomes necessary to procure a Cloudflare subscription.
No, however, you could attempt to connect using the aws cli s3 command or a management tool like s3browser to verify if downloading and uploading function properly. Discourse rarely utilizes advanced S3 features.
I refactored the project by putting the warehouse git into app.yml, but the plugin still didn’t install. Is it because of the unstable connection to GitHub on the domestic server or some other reason?