Hi Baniya,
Could run a pmm-server container with directly specified env variables?
e.g.
docker run -d -p 80:80 -p 443:443 --name pmm-server \
--restart always \
-e GF_SMTP_ENABLED=true \
-e GF_SMTP_HOST=smtp.gmail.com:587 \
-e GF_SMTP_USER=test@gmail.com \
-e GF_SMTP_PASSWORD=password \
-e GF_SMTP_SKIP_VERIFY=false \
-e GF_SMTP_FROM_ADDRESS=test@gmail.com \
-e GF_SMTP_FROM_NAME=Grafana \
percona/pmm-server:2