Issue while setting root_url

hey guys , I am new to grafana and I am having issue while setting up the root_url . Browser is throwing the error “can’t find the server”. Without setting the root_url , i am able to open grafana dashboard from localhost .

Please help in resolving the issue .
Thanks !!

In grafana.ini file , i am doing below settings :

protocol = http
;http_addr =
http_port = 8088
domain = mygrafana
;enforce_domain = true
root_url = %(protocol)s://%(domain)s/
router_logging = true