Arduino Uno + IDUINO Yun Shield

Hi, I just purchased Arduino Uno and Yun shield from geeetech
I've got my Uno connected to serial and wifi through Yun shield
It seems like verifying and uploading sketches work, but for some reason
some sketches would be giving me this error

Unable to connect: is the sketch using the bridge?

I've got my serial and everything connected... So I'm not too sure what I'm doing wrong
Also, I was trying out the bridging for Yun shield trying to access url endpoints
but this is also giving me an error

Could not connect to YunServer 146 Connection refused