Sort It Apps as a company and as a product no longer exists. The apps hadn't been updated in over 5 years and were incompatible with the latest versions of both iOS and Android. The server, data, and purchases for Sort It Apps were shut down by the company in September 2023 and are no longer available or online, and the company no longer exists. Warnings about Sort It Apps no longer being supported had been going out for well over a year prior to whatever e-mail addresses that were in the database.
The app listings within Apple and Google's App Stores have been transferred to iCollect Everything, LLC, which is why your app may have been recently updated with a new logo and look and your old collection may be missing. iCollect Everything is an alternative to the prior Sort It apps that you can use.
NOTE: All data from Sort It Apps is no longer accessible. You will need to create a new account and input your data again if you wish to continue with iCollect Everything, and any old purchases won't be transferrable.
If you don't yet have an iCollect Everything app installed, you can find it here:
If you have a CSV export file of your collection as an old backup, email iCollect Everything with that file and they can import it for you after you've created an account.
Again, the Sort It Apps company no longer exists and any collection stored with Sort It Apps has been deleted.