"Broadband ADSL Quality" item doesn't work

[stevage]

These errors appear in the server log:

{ Error: unable to verify the first certificate
    at TLSSocket.onConnectSecure (_tls_wrap.js:1060:34)
    at TLSSocket.emit (events.js:182:13)
    at TLSSocket._finishInit (_tls_wrap.js:639:8) code: 'UNABLE_TO_VERIFY_LEAF_SIGNATURE' }