This is because you do not have the pro version activated. In fact, you’re on an out-dated version of the free version of Startup.
If you just recently purchased the pro version, keep in mind that it doesn’t automatically upgrade your free version to pro. You have to download and install the pro version like a separate theme:
https://startupwp.com/topic/installing-your-theme/
There’s arguments for and against a paywall structure like that that would allow for auto-upgrading to pro, but this is currently against the wordpress.org theme guidelines.