"Something went wrong. Try again later" error message
If you are unable to connect your Etsy store - e.g. due to the following error: "Something went wrong. Try again later" - it might be that your Etsy store is not fully created. It is not possible to link an Etsy store that has not been fully set up, i.e. you need to go through all the 6 setup steps in Etsy and create a listing to launch the Shop:
Cannot connect a second Etsy store
When you are connecting your Esty store (especially if you have more stores/accounts) you should be logged in to the same store you want to connect to your Gelato (or not be logged to Etsy at all, in which case, the system will ask you to log in during the process). If you are logged in to a store that is already connected to Gelato and use an option to add another Etsy store, the process will fail (as the system will think that you want to connect to an already existing store).
It is important to note as from the users perspective, it will seem that your request to connect to the store will be ignored, as after logging in to Etsy and verifying the request with a security code, the page will take you back to the Gelato store list and no new stores will be visible there.
If that happens to you, please log out of the current Etsy account and log into the second store before trying to connect that second store to your Gelato account.