We will be enforcing TLSv1.2 as the accepted secure protocol for all connections to Shotgun hosted sites starting May 15, 2019. This work will prevent tools that use older versions of Python from connecting to Shotgun. Web access to Shotgun will remain unaffected using all modern browsers.
You can see our full announcement here: https://support.shotgunsoftware.com/hc/en-us/articles/360020119213
This enforcement is mandatory for all sites.