Osmarender displaying large blank tiles

Hi I am new to the OSM project and have been adding updates to my local area. I have converted to JOSM and find it relatively easy to use. Since making changes and uploading I have noticed Osmarender is now displaying two large blank tiles with very little detail. You can locate the area I am refering to by searching for Sutherland, New South Wales, Australia. Did I do this and how can the missing detail be restored?

Thanks for your help