The type of net connection is not important. It must not be great differences between the live trade and backtest. If you can, post please screen shots of the trade and backtest to see where is the problem.

I'm not at home now but I will make screen shots in the evening. Anyway I will explain you what's happening. I have 2 strategies (15min, 1h) working on the same account on EURUSD and both have this kind of problems:

first strategy:
on live: has 4 positions opened and closed all together on the same time yesterday at 15:30.
on fsb: at 15:30 add one position more...

the other one:
the strategy must open every night at 00:00 a position.

live: yesterday opened 2 positions
fsb: yesterday opened only one position

other problem is the opening time. there are 5-30 min difference between fsb and live trading.

Yesterday evening I started to think maybe these occurred because of my wireless connection....

any idea?

What are custom indis? If this means custom indicators, the question is, what are custom indicators? 

no, I added no custom indicator

hello Mentosan, is possible for example that when you send the order, your broker don't open the operation because it arrive with little delay (not because your connection is wireless, but because  you don't have a vps) and the broker make a requote of the ask/bid price, so don't accept your order because it is different, I think that if you can send the order with a minimal slippage on the price ,it can processed and so you can see that the different is little.
For example if on the market the price go up strong if you make the order directly on your broker platform is very hard that you can open the order because the broker is continuosly make a requote of price this make the big difference from the simulation and the real market (plus other thing).

I think that, if is possible mr. Popov (the Mind) must integrate the slippage on the order that the fst send to the broker so is more secure that the system can make correctly the strategies.