Invalid Token Sessions affecting Paypal setup

Hi,

I have spent days trying to fix this and have viewed all the Posts etc and my problem is still not fixed.

I am not a coder but have basic skills.

I am continually getting Invalid token session. Please login again. I need to fix this.

My coder says it is affecting my Paypal setup. We have tried different paypal accoutns that all work on other sites but it does not work in OpenCart. Please help. Desperate Desperate Desperate

Thanks