having trouble with https

From some days, my site reverted its certificate to the “invalid” self-signed default one. On the certificate server, it was all right but my site reverted back. Can someone help me?

website: https://moonlightcapital.ml
account name: rfgd_18948836

It looks like your website is indeed using the default certificate again. Have you tried to reinstall your own certificate?

I did, but with no success