This message is coming from Airtable API and it means you're hitting their 5 requests/sec limit. This is expected if you're embedding the extension in a relatively high-trafficked website.
This issue is more likely to happen if you have multiple public extensions (e.g. portals) embedded, and they are all being loaded at once.
To potentially avoid this, you might consider "lazy loading" your embedded extensions as a possible workaround.