Improved error handling and one fix in order to detect #1103 issues

Take a look at this, @Kartones . This is mostly error handling improvements, including some deleted error shallowing that might be responsible of not detecting what's happening under the hood. On one hand more errors will be shown, but on the other mail won't send a not working, success link, and we should be able to see better logs.
is this from a merge? because @rafatower is making changes to query_batcher, so please review this part with him if proceeds