Okay, now that you have posted the file I see what's wrong.

You have an actual space there in your image.

Here's how you fix your issue:

1. Select your image
2. Right-click and select Isolate Selected Clipping Mask
3. Now select either the left or right side of your image and move it so that the gap is closed.

That's it! Your image will no longer have this gap.

You may experience a thin line that "appears" to be there but is in fact not (you can test this by zooming all the way onto the line.)

Okay, now that you have posted the file I see what's wrong.

You have an actual space there in your image.

Here's how you fix your issue:

1. Select your image
2. Right-click and select Isolate Selected Clipping Mask
3. Now select either the left or right side of your image and move it so that the gap is closed.

That's it! Your image will no longer have this gap.

You may experience a thin line that "appears" to be there but is in fact not (you can test this by zooming all the way onto the line.)