Can't get SSL/TLS certificate

i’m connecting my app on a domain hosted by Squarespace.

App name:
Domain name:

After i got the DNS right, now i can’t get the SSL/TLS certificate, i’ve this error message: " We could not provision a Let’s Encrypt certificate for your custom domain."

Can someone tell me how to fix this problem and if there is something to do on Squarespace also?

Thanks in advance,

Your NS records for are pointing at:

If you’re intending to use external DNS, they should be configured to point to only your squarespace nameservers. Once you update that the SSL certificate should provision automatically.