After disabling TLS1.0 new and existing OData Excel connection are no longer functioning correctly with the errors “The underlying connection was closed: An unexpected error occurred on a send” or “The request was aborted: Could not create SSL/TLS secure channel.”
This is not a CRM specific issue and is a result of some 3rd party applications and local server configurations being configured to communicate over TLS 1.0. To resolve please refer to the link below explaining how to update .NET Framework and force it to use TLS 1.2 communication.
DBA's or Network admins will need to install .NET Framework v4.5 and make changes to the web server registry to disable .NET Framework 4.0. The end result is that .NET Framework is forced to communicate over TLS 1.2 per v4.5 protocol.
Steps to Duplicate
1. Disable TLS1.0. 2. Get an OData link from an adhoc query. 3. Attempt to create a new data connection using URL. 4. Observe error “The underlying connection was closed: An unexpected error occurred on a send. “