Thank you for your inquiry. New members have a post cap limit until they reach a post threshold. We don't advertise the specific post threshold, as it can change and is in place primarily to prevent spammers from abusing the post system. We don't want to make it easy to circumvent, but it is very minimal. Your limit will reset 24 hours after you received that message.
Alternatively, you can partake in the community discussions to raise your post count, and ultimately, this will remove the limit on posts for your account. Happy posting!