hCaptcha DNS issue for mainland China

looks like we can’t test “that name server” from outside of the network

You imply that I only provided 1 name server, did you see the other screenshots I posed 3 days ago? Theres 8 distinct name server IP’s in the screenshots I provided:


Keep in mind the inaccuracies of such tools that might be sending you down the wrong road in getting this fixed.

In addition to reach out to network operators like you have said, I’d also suggest you speak with your contacts at Cloudflare who might be able to shed some light on the failure points when operating in the Chinese networks.

All too often we see amateur mistakes made by technicians outside mainland China who don’t realise the mistakes they’re making and cannot see the issues for themselves even when told about it.

If you are not familiar, please speak to someone who is. In my opinion it is totally unacceptable for a technology company to experience a significant outage for months and still be in the bleeping investigation phase while this issue continues to be on-going!

It doesn’t seem like @hCaptchaSupport are taking this issue seriously.

@hCaptchaSupport it has been 3 days since I’ve heard anything from you

@hCaptchaSupport …?

@hCaptchaSupport it’s been a week without a response

Hello, we’ll let you know when we have an update.

It has been over 2 weeks since I provided the IP and DNS information you requested. Whats happening with this matter!?

@hCaptchaSupport Any update?

@hCaptchaSupport It has now been 1 month since posted this issue on this forum. And it has been 70 days since I first raised the issue.

What is happening with this matter? Do you have any idea whats wrong yet?

Since providing the IP’s and DNS info 23 days ago, I have tested daily on many different networks and devices and am still seeing a 100% outage in Chengdu. I have tested on a few locations outside Chengdu, and other provinces with some failures but mostly success. This issue seems to be limited to mainly the Chengdu/Sichuan network.

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Some dynamic routing changes rolling out over the next month or so will likely work around this issue for you. Our monitoring site in Chengdu looks normal, though.

@hCaptchaSupport Are you positive that will fix the issue or just making an assumption? Depending what your referring to by that and how its being accomplished it likely won’t fix the issue.

The issue is still happening to this day. Probing DNS gets and on some China Mobile networks it gets

@hCaptchaSupport The issue continues to happen.

@hCaptchaSupport Any update yet? I continue to have this issue on a daily basis. Today I tested again on multiple networks around Chengdu whilst out, still every test failed. I used a different device at each location (5 devices). Tested on 4G China Telecom, 4G China Mobile, China Mobile Fibre Business, China Telecom residential fibre, and at the Apple Store. All locations the issue persists.

@hCaptchaSupport Any update yet?

The fact that you are being ignored when an issue has been carried for this long is rather concerning. Do you know how many users could be experiencing this issue?

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@hCaptchaSupport is using CloudFlare for their DNS. Do you see similar failures on other sites that use CloudFlare for DNS? If yes, then this is an issue to raise with CloudFlare.

Other sites on Cloudflare work fine. Cloudflare website itself also works fine. The only issue we have with the Cloudflare website, or other websites using Cloudflare is the hCaptcha.

Often its is required to complete a hCaptcha to login to the Cloudflare website but the hCaptcha never loads (see the screenshot in the sixth post). Or for websites protected by Cloudflare in the “I’m under attack” mode will present users with a hCaptcha before entering the website, yet the hCaptcha never loads (see the screenshot in the first post.)

Just because hCaptcha are using Cloudflare DNS doesn’t mean they’re infallible for misconfiguration, and doesn’t mean they can’t have issues elsewhere.

Cloudflare themselves iterated a few points of issues for China DNS and routing in a somewhat recent blog post. I would assume hCaptcha have some kind of technical representative at Cloudflare assigned to them, so if they just cared enough about this outage issue to raise it with them, then they might have got it fixed already.

I can confirmed that sometime we face the same issue as the first person of this topic said when we using Cloudflare WARP in Vietnam.
When use with warp option, it will randomly connect to some Hongkong IP and then when access some website, it will ask for captcha but the captcha does not load.
Some website using “Under Attack Mode” mode will show captcha when access.

Well, a good test for hCaptcha would be to change DNS servers temporarily. Or set up a separate test server with different DNS.

Edit: I am trying to figure out how to speed up DNS resolutions in China so at least I am glad to know CloudFlare DNS does not fail there sporadically; and that it is limited to hCaptcha, in your experience! So thanks.

If the issue is specifically with hCaptcha’s website, could it be possible that it is blocked by the ISPs? Just a wild guess.

@casper the issue seems limited to the DNS responses being or which your right in thinking it could be blocked since DNS level blocks are one of the most basic methods of blocking websites. But I don’t think this the issue, at least not intentionally because the DNS responses around other cities in China don’t have this issue.

My testing is mostly carried out on real networks around Chengdu so my sample in other cities is limited to where I’ve traveled in the recent few months or what friends/colleagues have been able to test, but from my testing it’s pretty much affecting Chengdu 100% and other cities intermittently if at all.

Possibly its some kind of blocked issue but unlikely. Using any other DNS server except for the China Telecom/Unicom/Mobile defaults will solve the problem.

Other networks in Chengdu don’t appear to be having this issue. Testing on servers on Alibaba, Aliyun, etc… in Chengdu/Chongqing also don’t appear to be affected.