Question about the DNS zone, CNAME, Systeme.io... (everything's red)

Question about the DNS zone, CNAME, Systeme.io...

Yesterday, I purchased a domain name on OVH to link it to systeme.io. 

They then asked me to add two CNAMEs, which I did. At one point, OVH asked me to delete two conflicting entries for the first CNAME, which I did. The two CNAMEs were then applied. I then had to apply a redirect, which I also did. Finally, they told me that a redirect already existed and that I had to overwrite the existing one to apply the new one, so I clicked OK.

A few minutes later, I checked the CNAMEs on DNSChecker to see if everything was OK: I saw some areas in red and others in green, but everything seemed normal since it had only been a few minutes.

I checked again a few hours later, and now everything was red for the CNAMEs. 

I wonder if I've done something wrong and decide to reset my DNS zone with minimal entries and delete any possible redirects to have everything in “basic” mode. 

In the end, it's been over 8 hours now and everything is red on DNS Checker.

I have no idea if I did something wrong, since I did everything exactly as written in the system.io tutorial, and even after resetting, all the CNAMEs are red (see screenshot).

If you have any ideas, I'm all ears.

Thank you very much.