1. First login to your Vesta Control Panel
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2. Go to “WEB” tab, hover over the domain the Certificate has been issued for and click on “Edit” button.
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3. On the next page locate “SSL Support” tab and check it.
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4. Now your Certificate, Private Key (which you saved after CSR generation) and CA Bundle files should be put into the corresponding fields.
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Your certificate has been installed and you can check it using these tools:
https://sslchecker.com/sslchecker
https://www.ssllabs.com/ssltest/index.html
https://certlogik.com/ssl-checker/