https://support.wati.io/l/en/article/ikyb3db1td-what-are-possible-common-errors-in-embedded-signup-flow

A. Errors in the creation of the business manager account.

<aside> 🚨 An error occurred while processing this request. Please try again at a later time.

</aside>

This is an unclear error that needs further assistance. The company account creation could have failed for several reasons.

==> If you have this error, please use an active Facebook account or contact support to resolve it.

<aside> 🚨 You have reached the limit of the number of businesses you can create at this time.

</aside>

There is a limit to the number of business accounts you can create.

==>Please use an existing business account or delete/close unused business accounts.

<aside> 🚨 Your Facebook account is too new to create a business account. Please try again in one hour.

</aside>

New Facebook accounts have to wait a while to create a business account.

==> Please use an existing and active Facebook account or wait a few hours before using your new account. The new Facebook account can be actively used during the waiting period.

<aside> 🚨 We limit how often you can post, comment or do other things in a given time to help protect the community from spam. You can try again later.

</aside>

Your Facebook account has been flagged for suspicious behavior.

==> You need to use an existing, active Facebook account with no previous problems.