The message "The monthly limit for your workspace has been reached" indicates that the monthly "Export rows per month" credits limit was reached for the connected workspace.

In order to display SEO metrics, the extension consumes the "Export rows" credits from your workspace/account (one "Export row" per search result or page browsed). You can check the consumption in your limits and usage.

Purchase additional Data export credits, or wait until the usage resets at the next billing date.