When I zoom in I can see your via is not connected to the plane (there is a gap between it and the flood) so this is a real connectivity error.
On the <Tools><Options>(thernals) dialog, is 'routed pad thermals' unchecked? If it is you may have a tiny trace attached to the via under the pad on the top layer. You'll need to delete that trace before PADS will connect it with a thermal. You can quickly test this by checking 'routed pad thermals' and see if the pour connects then.
Oh, I thought the 'purple' color was a combination of the colors below it showing an opening.
I might have my logic backwards on the 'routed pad thermals' so you might still want to try unchecking it and pouring again, just for a test.
When there is a connectivity error, PADS sees a net broken into two pieces. you might be connedted properly at the warning you are looking at, and the disconnection may be near the other warning. You nned to trace the conection between the two warnings and see where the break is.
Remember, verify design only checks what is on the screen, so if you don't have the entire PCB in view it can miss errors that are present.
Thanks again for the quick response.
The problem was a copper plane below the top layer which was assigned the isolated ground but not connected. Once I connected to the plane, the error went away.