Heads Up :
The post you are writing will appear in a public forum. Please ensure all content is appropriate for public consumption. Review the employee guidelines for the community here.
TLS 1.2 is not supported (and never will be) on the 7900 series phones.
https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/uc_system/unified/communications/system/Compatibility/TLS/TLS1-2-Compatibility-Matrix.html
Move to 7800 or 8800 series is y...