We are experiencing a fatal error when sending API calls:
System.CalloutException: Remote host terminated the handshake
This issue first appeared on October 22, 2024, in our orgs, with no changes on our end that could have triggered it.
We have already updated the server's TLS to 1.2 and set the correct Cipher Suite as outlined in the following link: Salesforce Release Notes on TLS and Cipher Suite.
We also verified that the SSL certificate is still active.
Despite these updates, the API call is still failing.
Could anyone advise on any additional steps or checks we should consider? Any insight would be greatly appreciated.
Thank you in advance for your help.
Sushil Kumar (UKG) 
Forum Ambassador
@Yara Akiki I am assuming this is call from SF to one of your internally hosted service. Have you checked firewall rules if anything changed over there? Sometimes SF IP addresses are allow-listed in firewall to allow access. And also if you have moved to hyperforce recently, You may need to reference this.
