Peer Not Authenticated

Hello --

Last year, we had a process model exposed as a SOAP web service where a web form would POST to it, and that would kick off a process model. That worked from February until early January, when the campaign ended.

I made some updates to the application, and I can still post to the web service via SOAP UI. But, when I attempt to POST from the webform, the application servers says the request fails with "I/O Exception: peer not authenticated"

Last year, I didn't have to enter anything in to CORS, but I did that, and it still doesn't work. I attempted to upload my SSL cert from my web server to Client Certificates, but Appian complained it was the wrong kind of cert.

Any help in something I can try to get this to work would be appreciated.

Thank you!