My free trial account is telling me "We were not able to load more envelopes." Is there a limit to how many envelopes you can send using the free trial or is it based on file size sent? Thank you for any advice/comments/suggestions provided.

The article did not mention any limits based on number of Recipients only the number of envelopes. Is it possible you sent another and voided or deleted the envelope, which would still count against the total, it doesn't necessarily have to be successfully completed envelopes. My suggestion would be to create a DocuSign Support case and see if they can extend or add envelopes since you are still testing the application.