HTTPClient POST APPEND Error

[ColinCR]

I have been using a data posting daemon for many, many years with issues. At 7AM PDT, all remote clients began showing an Error: 

The above error is from a simplified executable I wrote today that does nothing but send a message, with jsonified request as: 

{"client_id": "clientname", "client_key": "clientkey", "action":"get_client_messages"}

Snippet shown below. 

Interestingly, this executable will run from my development laptop. I can also send a post data request from something like Firefox, or other post requests on the net. I also have non-labview clients that are posting just fine. So, something is broken within that vi and I can't get inside to figure out what it is. 

Anybody have a workaround or an idea of what is going on here?

Thanks!

[ColinCR]

Ok, this actually appears to be either error 363506 or 363506, which is a "Could not verify the authenticity of the server" error. Why this has changed at one time of day? I have no idea. Web site is on my servers, green lock, letsencrypt renewed, all that. What is LV's problem? 

Temporarily, I can disable the server authentication in the create client vi, but this is obviously not ideal. What gives?