maintained bulkhead problem

[liamj_6]

in the community building i manage there is a round 28w 4 pin bulkhead, maintained for 3 hours, that had stopped working. I have replaced the bulb but still showing a red light. It works on emergency test mode and is lit dull as normal but in normal mode it doesnt work at all. Is there something i have forgot to check or could it be a common fault. Also not an old fitting.
Thanks