My server doesnt appear at the providers list with servers-slippage.
Is it way to check the slippage before subrscribe?
You apparently don't know what slippage is!
It's the difference between the requested open price and what you actually get fill with. With an honest broker it will average zero.
You are obviously reffering to the signal's tab slippage, which is the difference in points, between the average price of the signal's positions and your broker's data.
If your broker is not listed in the signal's slippage tab, then you can proceed and copy that signal at you own risk or set the deviation/slippage setting in your MT Tools >> Options >> Signals somewhere between 0.5 and 1.0 to avoid big differences in prices.
"At my own risk"
Slippage is a regular part of trade, No one broker without slippage but a broker with more Lp's in circle usually have less slippage.
But it should be clear that you can find broker without slippage (False)