This project is read-only.

SPrello won't activate


I am looking to use SPrello in a SP2013 SP2 on-prem farm. I successfully uploaded the SPrello Sandboxed Solution however the Activate button is disabled so I am unable to activate the solution. I do have other Sandboxed Solutions installed and activated so it's not an issue with Sandboxed Solutions in general, just something with this particular one. Has anyone else come across this issue and if so how did you resolve it?