The site is a DDNS provider. Though my script has been working for quite a while, I recently discovered that the "/tools fetch" invocation is now failing on (I think) the TLS handshake. I suspect that myaddr.tools has recently started supporting only 1.3. Does the "fetch" tool support TLS 1.3 only servers?
I believe Mikrotik doesn't support tls 1.3.
From what I gather, there aren't really plans to do so either... (Tls 1.3-only is still pretty rare.)
I believe Mikrotik doesn't support tls 1.3.
Are you sure TLS 1.3 is required?
The other possibility is you're using host= and mode=https in the /tool/fetch. Recent RouterOS versions want you to use just url=https://xxx.com instead.
Thank you for the responses. I was using the mode=https with the url parameter. I tried removing mode and am getting the same problem. I'm not sure about the TLS version, but the URL I'm using does work when I invoke from a browser. I've switched to DuckDNS and have that working now.