SSIS job runs successfully but doesn't load data

I am running a job from SQL Server Agent and the job runs successfully. However it doesn't load any data (in my case Excel files from a local folder). I created a new Proxy Account to run this job but it still doesn't help. I checked that the proxy user has SYSADMIN rights and also permissions to access the Excel files from the folder. I run the package from Visual Studio and it runs successfully and the files are loaded. This is done manually every time. We want to fix this issue. Can someone please help me with this. I can share any more information as needed.