A paid singular Zoom account can't host multiple meetings at the same time without the account having multiple paid Zoom licenses connected to the singular Zoom account.

The Zoom company themselves have noticed this issue from customers and have written a response on it which you can read here: https://support.zoom.us/hc/en-us/articles/206122046-Can-I-Host-Concurrent-Meetings-
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After having multiple paid Zoom licenses connected to your singular Zoom account you should then be able to have multiple meetings at the same time. Although soon Servv will have the option to add multiple Zoom accounts and thus you will be able to use those accounts to host multiple meetings at the same time.