You probably reached or exceeded the keyword limit on your account - don't worry, we've got you covered!
If you want to add another project keyword, then you need to either delete the old one(s), upgrade your current subscription, or buy extra keywords to increase your limit.
To do so, go to your Account Settings
and select Your Subscription and account. You'll be able to upgrade your limits over there.
We hope this article has been useful to you! If you have any further questions or need help, please don't hesitate to get in touch. You can reach us via email at email@example.com or send us a message using the chat box on the bottom-right side of your dashboard.