ETL Runs well on one server and fails on other.

I have an ETL using config file, it has source and target folder path in the config. I build the full path within ETL using variables by adding file name to source and target path  

In foreach loop I get the file_name in a variable, I use source_path passed from config file to build full path source_path\file_name

</Configuration><Configuration ConfiguredType="Property" Path="\Package.Variables[User::source_path].Properties[Value]" ValueType="String"><ConfiguredValue>C:\DataFile\Input\</ConfiguredValue></DTSConfigurationHeading><Configuration ConfiguredType="Property" Path="\Package.Variables[User::Archive_path].Properties[Value]" ValueType="String"><ConfiguredValue>C:\DataFile\Archive\</ConfiguredValue>

It is working perfectly on dev environment and failing on higher environment with err " Could not find a part of the path " I checked the access on folder target folder it is fine. I check if the pkg is reading from config, it is reading other variable values correctly. the setup on both the server is all same no change wrt folder structure etc.  Just I dont have visual studio on higher end server, I a running it through SQLAgent job by adding config file to it. 

SQL Server 2016, VS 2015 is what we are using and we are recommended to use config file and store pkg on server in file. 

Neil