Description: Geek, tech, programmer, business owner. Serial starter of things. Occasional finisher. Oh, and please don't call me Dave.
I started to see errors on our calls to the Xero API, with status 412 returned. The initial clue was in this Xero Community post .
On windows 7 machines or older machines, you may need to install a fix to ensure that windows can handle TLS 1.1 or 1.2. I usually recommend this update as a first step as it mitigates not knowing how the underlying code, wrapper may work.
This led me to a post about TLS versions , with a useful piece of code to check the TLS version of your server: