DocuSign Accounts can have envelope limits such as 5 envelopes per month. This is typically set by the Account plan type and can differ, but if you exceed the limit and try to send a 6th envelope when your limit is 5 then you will get this error message. So you either wait until the reset time which will reset the envelopes and allow for the 5 envelopes per billing cycle or contact DocuSign Sales to increase your limit which may require a change in DocuSign plan. Here is an article on exceeding envelopes...

https://support.docusign.com/en/articles/What-happens-if-I-exceed-the-envelope-limit-on-my-account-What-is-the-charge-for-additional-envelopes