If you see an error report dialog with a message that looks like “EPROTO … unsafe legacy renegotiation disabled” when starting up Exploratory, that typically implies that you are connecting to the internet through a proxy server, and the proxy server does not support the security-related SSL feature called TLS Renegotiation Indication Extension.
If this started happening all of a sudden, it is possible that there was some change in the configuration of your proxy server that would intercept SSL traffic from within your network to the outside internet.
If that is the case, please talk to the administrator of the proxy server to see if they can support TLS Renegotiation Indication Extension to resolve this issue.