I have been using Manager for a little over a year and never quite experienced this issue so it may be something simple.
When I am trying to run a VAT (Manager calls it tax) Report, there is absolutely nothing showing up, its all zero’s. I have tried everything, all the transactions show in the Payments / Receipts tab but the reports aren’t running?
The Tax Summary by itself provides no evidence of cause. It’s the result.
Contrary to your statement, this screen shot shows no transaction within the date range of the report. The report runs from April 5, 2018 to April 30, 2019. The screen shot shows postings to the Tax payable account from May 10, 2019 to May 30, 2019. While you may have transactions that fall within the date range of the report, you have not shown them with this screen shot. But perhaps you reversed the order of screen shots #2 and #3? If so, did you set a Start Date under Settings? If you did, the program will ignore everything before that date except sales and purchase invoices, which it will use only for setting starting balances on Accounts receivable and Accounts payable. This could explain what you are seeing.
Now I definitely think you have reversed the order of your 2nd and 3rd screen shots. If this screen shot is actually what you described as #2, you need to show the Edit screen of one of those transactions circled at the bottom. Of course, if fixing a Start Date problem fixes your problem, you can ignore that piece of advice.
Incidentally, I see you are a few hundred versions behind on your software updates. I recommend updating. All forum advice is given based on the current version of the program. The program advances rapidly.