Error 523, but intermittently


Since this morning (May 25, 2021) around 10:00 am (GMT -4:00 Eastern Time), all the sites that I host give the error 523. But intermittently.

Sometimes the sites work fine and 5 minutes later, there is an error 523. A few minutes later the sites come back and fall back to 523 just after.

Yesterday and today this morning before 10:00 am the hosting server was working perfectly. Nothing has been changed on the side of the host server. The hosting server is located in the Canada region of Montreal.

The traffic has decreased by 10 times.

Do you know if I am the only one with this problem?

I am trying to locate the problem but since nothing has changed on the hosting server side, I am trying to find where it all came from.

Sites are,,, and other more.

Thank you.

May I ask who is the hosting provider?

Have you tried contacting them about the incident?

What does your server log files say?

Regarding Cloudflare returning 523 error, kindly see the suggestions on the below article:

May I ask is Cloudflare allowed to connect to your origin host/server?

Here is how to check it:

Cloudflare IP addresses can be found here:

I tried openning them right now, but for each I got “timeout” error from my Web browser (not the Cloudflare).

Allright, tried again and sweepstakes openned over HTTPS, concoursenligne also over HTTPS (but was redirected from HTTP, I suppose you are using Flexible SSL option here?), while appartqc I got 523 and 522 from Cloudflare.

Third try for appartqc it loaded over HTTPS.

I see these are WordPress sites, but do they have some caching plugin?
I assume they are hosted on some slower VM or shared hosting?
It takes long to load them, and possible they are heavey to load for the origin host/server?


Our Internet provider is Cogeco (Quebec, Canada). For the web hosting provider, the sites are hosted on our company’s servers.

The log files do not say anything about this problem.

At first I thought maybe a database problem but some of our sites are just html pages without communication with a DB server. Like This simple html site gives error 523.

The sites are also configured with DNSSEC. But as said earlier, before 10:00 this morning everything was working perfectly.

I have been trying for hours to speak with the support of the Internet provider and the phone hangs up …

These are Wordpress sites except which is a simple html. He too is in error 523.

The sites are on a dedicated Xeon server with 64 GB of RAM with SSD. Before 10:00 this morning everything was going very very well. High score on GTMetrix.

No updates, no PHP or SQL modifications have been done since or shortly before it stopped working.

The sites have been online for years and were working flawlessly. But since 10:00 this morning … 523

We brought back a snapshot from May 13th because the server is on a VMware server but dedicated only to our websites.

Even with the May 13 snapshot, the 523 error returned.


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