In ArcGIS Pro layout view, my OS Mastermap WMS layer appears very blurry. I need it at 1:1250 scale but it looks like this:

I need the image to be crisp and sharp. The exported image/pdf also displays blurry basemaps.
Same problem when using the open basemaps supplied in Pro.


When in Data view, these basemaps are nice and clear when zoomed in.