Important notice about google short link, please read it.

As Per google short link: Starting March 30, 2018, we will be turning down support for URL shortener. From April 13, 2018 only existing users will be able to create short links on the console. You will be able to view your analytics data and download your short link information in csv format for up to one year, until March 30, 2019, when we will discontinue Previously created links will continue to redirect to their intended destination.

As google stop this service app remove google link generate option, make sure you backup it or convert into other links.
As google stop short link option, we discontinue with our app as well.