Hard to tell between english as second language and photo, but it looks like
1. artwork not clamped tightly enough to board during exposure
2. exposure too long
3. developing too short
It is best to do a shorter exposure time first, develop it, use a vibrating toothbrush to gently rub during developing can help, then after developing and rinsing in water, put it under UV light again (no need for the artwork, just put all under UV) for about twice as long as the initial exposure and inspect, after the second exposure it will be easy to see resist still in places it should not be if there is and you can put it back in the developing solution for a short time with toothbrush to clean that up before you etch.
Fixing the developed image is a lot easier than fixing it after etching, so take your time after developing to very carefully inspect for any resist residue still left over, or any other problems.