Permission to install custom tab on Facebook

I tried adding a facebook jotform tab integration, but I received the error "This page does not have permission to install the custom tab"

What does this mean? Pls explain how I can customize my facebook page to allow

a jotform contact form tab?

This is caused by Facebook adding a rule of having 2000 followers/fans to create custom tabs.

The rule came as part of the 90-Day Breaking Changes on the Version 2.11 Update of Facebook, which was rolled out on November 7, 2017. The rule became effective on February 7, 2018.

You can find the changelog here. 

Related statement from Facebook for developers page:

At the moment, we can't do anything about this issue as it is being handled on Facebook's side.

However, if you are experiencing this issue with your Facebook page that has more than 2000 followers, please let us know.