400 Error : The specified resource was not found

Now that the apps are back online, this opens up two topics :

I had asked how to deal with no connection. I was directed to catch “Network Error” (How to catch a network error exception?). However, during this outage, it did not work as planned. Probably since the errors thrown were different. This time, I have managed to catch the following message : "Custom business logic execution has been terminated because it did not complete in permitted time - 15 seconds ". Is there a list of the error messages somewhere, or better still, could there be a Codeless block for catching a connectivity issue ?

And finally, I have scoured the forums for information about offline capability. I understand Local Storage could be a possibility. Yet I have tried it and once on a mobile device this immediately produced a "QuotaExceededError: the quota has been exceeded. " I found this to be probably linked to the fact that the Local Storage was way insufficient. Do you have guidance on a way to plug Backendless into a local Sqlite database ? I see this as the only practical way forward - if I manage to understand how to set it up.