Data Gateway not working properly

I am facing very strange beghaviour with data gateway, sometime it work and some times it is throwing error. 

 Error

I have tested my gateway connection which showing connected but when I refresh it then I am facing this issue. Below is the screen shot of my refresh history which is showing using the same gateway my dataset has been refreshed and failed few times in both scenario on demand and scheduled.

Refresh History

I have only single source of data in my gateway data source :

Data Gateway

I have tried unistalling and installing gateway multiple times but it is not helping.

Please help.