Hello! Saw this Failed to generate cert post and saw someone solved it manually and I am running into the same issue:
The domain troubleshooting guide can help with most custom domain configuration issues. You might be able to use that guide to solve it before a human is available to help you. Then you can come back here and share the answer for bonus points.
You can also use v0 to narrow down the possibilities.
Lingering DNSSEC from previous provider. Had to contact support to remove the record 
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