Mailhook delivery failure

Just started getting some delivery failures when sending to mailhooks. Is there a chance of a sending domain being blocked so that the mailhook is not accepting it?

No SMTP servers were available for mailhook-latenode.com. Tried route3.mx.cloudflare.net, route2.mx.cloudflare.net, route1.mx.cloudflare.net.

This behavior is seen through one service but not through a different one.

There is a DNS issue

Found a workaround by changing the sending domain IP address. Still wondering if the previous IP was blocked somehow. Hopefully it doesn’t happen again.