When an account has been manually suspended by a moderator and the user is trying to post a question via /questions/ask, it says:
You have reached your question limit. Sorry, we are no longer accepting questions from this account. See the Help Center to learn more.
The screen looks the exact same as it does to a user subject to an automatic question ban. The help center link points to the article on automatic question bans.
It would be clearer to say that the account has been suspended, e.g.:
Sorry, we are currently not accepting questions from your account because it has been suspended till 2021-04-29.
preferably with "suspended" linking to the mod message stating so.