I tried to issue certificates on testnet. It successfully issued certificates before, but it just didn’t work sometimes with the exact same config settings. And I tried a lot of times, it worked occasionally, almost drove me crazy.
Sometimes, those blockchain explorers can be pretty flaky. Your configs are probably fine, but you might want to try to hit some of those endpoints manually (with curl or maybe a browser) to see what kind of response you’re getting at the moment. I might be missing something, but it’s usually the public blockchain explorers.
It can be a little bit tough to figure it out from the code, but if you hit, say, the Blockexplorer API directly, it might come back either with a JSON response payload, or with a 404 (or something else). They can flake out sometimes, so if you’re seeing this behavior in cert-issuer, it might be worth checking those sites to see if they’re up.