This can be achieved by binding a custom domain name. For more information, see Enabling Custom Endpoints.
The feature of configuring HTTPS for custom domain names of COS is being upgraded. Currently, certificate hosting is supported in public cloud regions in the Chinese mainland and in Singapore, and will be supported in other regions in the future. For regions that do not support certificate hosting yet, you can configure a reverse proxy for the domain name by referring to Supporting HTTPS for Custom Endpoints.
COS currently does not support returning the access links of custom domain names after files are uploaded. However, you can implement the feature by splicing access links and using custom domain names to replace default domain names.
If you use the COS V5 console and a JSON domain name is configured, the COS V5 console cannot display the new domain name. Check whether the JSON domain name is configured in your bucket. If so, change the JSON domain name to an XML domain name.
Only one CNAME record can be configured for a domain name. Therefore, you need to delete the resolution relationship between the domain name and the lightweight server first and then bind the domain name resolution relationship to the COS bucket.
After being configured, domain name resolution or CNAME may take several minutes to take effect. You can wait a while and try to access your bucket using your custom origin server domain name again. If the problem persists, you can log in to your DNS console to check whether the resolution relationship is configured correctly.