Issue with grafana . Not able to send slack notification behind proxy but the curl request is working fine from the server

Issue while sending slack notification behind proxy . Not able to send the notification but the curl request is working fine from the server .

What all the proxy settings need to be done .

I have added the export http_proxy and https_proxy to the /etc/init.d/grafana-server file

Also added these proxy in environment variable . anyone please help