Unrelated to the certificate problem
Why don’t you add a domain to Cloudflare again and use their certificate?
which is (if I see correctly) generated recently
In order to prove domain ownership, it is necessary to change the NS to ours
and then once a domain is added here to the hosting (you have already done it) you can use Cloudflare and their NS
and in the DNS settings of the CF then direct the CF to the IP assigned to you by this hosting.
Then you do this:
And then you don’t have to manually create certificates every three months, but Cloudflare does it automatically plus other benefits of CDN.