Hi aruna1,
you're making your life tough using a grid size of 3mm for the PCB layout.
Most parts are manufactured using imperial measurement. Using a metric scale routing becomes extremely difficult and ends in a never stopping "angle" and "overlap" error list when performing a DRC.
I suggest to delete the PCB and create a new one. Use a grid size of inches and a fraction thereof. If you're used to metric scaling use the windows calculator to define the grid size in mm instead of inches.
1 inch equals 25.4mm, 1/2 inch=12.7mm, 1/4 inch=6.35mm etc. Using the equivalent metric value traces will be straight from pin to pin. Otherwise the router has to jump to "snap" and makes funny bends.
Ratsnesting your designed PCB there are lots of crossing airwires, meaning routing will become almost impossible unless you use multilayer.
If you must do that because of a prescribed position of connectors you should really think about a multilayer board design.
Boncuk
P.S. No wonder the file size of the zip file was very large. You also zipped the backup files!