Browser and server share no acceptable encryption method.
WHAT IT MEANS
The client offered a set of encryption options and the server accepted none of them, or the reverse.
WHEN YOU SEE IT
An old browser or operating system connecting to a modern server that has disabled obsolete protocols and ciphers An old device such as a payment terminal or embedded system Occasionally, security software interfering
WHY THE SERVER REFUSES
Obsolete protocols and weak ciphers have known vulnerabilities. Accepting them to accommodate old clients would weaken security for everyone.
WHAT TO DO
If it affects one visitor with an old device: they need to update. There is no safe server-side fix.
If it affects an integration, such as an API client or a legacy system connecting to you: that system needs updating to support current TLS.
If it affects many visitors, something is genuinely misconfigured. Run an online SSL test, which reports exactly which protocols and ciphers the server offers, and open a ticket with the result.
WHAT NOT TO ASK FOR
Re-enabling obsolete protocols. We will decline, and you would not want it if the consequences were explained.