Problem with my email no receipt received!

Problem with my email no receipt received!

Hi

I have a apllication where users log their requests and automatically get a recipt on their mail. This is for a new request and when the request is put into status closed by me. But since Thursday the requestants and I have not recieved any mail!!!

Please help me. Next week I have to show the system to our key persons in our company and by then I hope the system will work!

BR Dennis