Just like every internet browser, Google Chrome can be extended with plugins, which add additional features, games, or new designs to the user interface. However, with each additional extension, you run the risk of impairing the browser’s functionality and causing error messages such as ERR_SSL_PROTOCOL_ERROR. If the previous solutions haven’t been successful, it might be worthwhile to deactivate the extensions until you want to use them again. If the SSL connection is then able to be successfully established, you know it was the extension that was blocking it. By reactivating the extensions step by step (including doing the connection test), you can easily identify what was responsible.
To access the extensions, click on the three dots next to the browser’s search bar, just like when you’re deleting the Chrome cache. From the drop-down menu, select 'More tools', then 'Extensions'.