Error 523 only from specific mobile network

All my users visiting from Nigeria and using a mobile network called MTN cannot access my website: It returns Error 523 for them. This is quite unfortunate since the majority of my users use that mobile network.

When I turn the DNS to the grey DNS Only; without the yellow cloud… meaning direct connection to my origin, the same users do not have problem visiting my website.

Can you please help me in fixing this issue? I have set the DNS correctly.

Please find the attached image… I don’t seem to be able to reach support directly. Any idea?

This issue is likely related to your local ISP provider. May I know where you host your website? Is it on premise at data centre or through cloud provider such as AWS? Print your trace route would help to understand this issue further.

In short, I suspect that your ISP has blocked CloudFlare access.

Hi Ang1,

I host my website at I am not the one being blocked, so it cannot be my ISP. Visitors to my website are the ones being “blocked” and this set of visitors use one particular mobile network called MTN in Nigeria.

From the screenshot, it seems as though Cloudflare was not blocked as indicated “working”. The issue lyes between Cloudflare and my host. I have contacted my host and they see no problem from their end because when I remove Cloudflare, the same MTN network users can access my website without any issues.

The Ray ID can be seen in the attached screenshot. I hope that a Cloudflare staff can attend to this as soon as possible.

Thank you.

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