Hello Erik. Can you post a screenshot of the issue. Maybe also of your UV's if you have any, maybe of the nodes. Things to take into account, applying the scale, applying the rotation maybe.
Martin Bergwerf
replied
Solution
There is a seam initially:
but if you Scale the X in the Mapping Node to 0, that should be gone...
Like Omar said, please post a Screenshot of the Node setup and 3D View if that doesn't work.