Allowing DLL Import for MetaTrader Platform
To use some external features, which is not provided from Meta Trader itself, you have to allow DLL Import. The steps are simple. You have to allow DLL import in two places in the MetaTrader. Firstly you have to allow them globally from MetaTrader terminal option. Then you have to allow them locally for each indicator or expert advisor. Check the screenshot below for direct guidline.
http://algotrading-investment.com/
https://www.mql5.com/en/users/financeengineer/seller#products