I mean - if all MT5 EAs does not work in your MT5 so you can check the following: autotrading for the EA, in common tab of the EA properties.
Allow Auto Trading — this option allows or prohibits trading using Expert Advisors and scripts. If it is disabled, scripts and Expert Advisors can work, but are not able to trade. This limitation can be useful for testing the analytical capabilities of an Expert Advisor in the real-time mode (not to be confused with testing on history data).
The option enables/disables automated trading for the entire platform. If you disable it, no Expert Advisor will be allowed to trade, even if you enable automated trading individually in the Expert Advisor settings. If you enable it, the Expert Advisors will be allowed to trade, unless automated trading is individually disabled in the Expert Advisor parameters
If everything is fine with the setting but EAs does not work (any EA - how many did you try?) so ask your broker (it may be the broker's limitation).
Where to check autotrading:
If you attached EA to the chart and you see "smiling face" so it is fine with autotading (in most of the cases):
If EA's face is not smiling and not happy so you can check everything once again:
It was for MT4 but MT5 is same with this case.
But there are some brokers which are not allowing autotrading so check with the broker too. And there are some symbols which you can not trade (S&P 500 for example, etc) - I means - there are some your particulat broker's limitation so it may be the reason as well.