We have a link we give to clients which uses https://get.teamviewer.com however this link is currently down.
Issue appears to be fixed now.
I'm seeing the same issue myself. I think it is an issue with Teamviewer themselves, it works fine in IE/Edge, but Chrome and Firefox both kick up security errors.
Running an analysis on ssllabs.com against get.teamviewer.com, doesn't give any issues at the summary at the top, but during the Handshake Simulation, it shows Chrome/Firefox/Safari all reporting:
Server negotiated HTTP/2 with blacklisted suiteRSA 2048 (SHA256) | TLS 1.2 > h2 | TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA | ECDH secp256r1