Hello.
I run Grafana in a docker container with mounted folder
–volume /var/lib/grafana:/var/lib/grafana
At the beginning everything was by default until I set up sending alerts to Slack.
Our grafana works under a reverse proxy and of course it’s not available by default address http://grafana.staged-by-discourse.com/…
So, I added env variable to docker run command
GF_SERVER_ROOT_URL=somelocaldomainname
and after container was restarted got wrong default link http://somelocaldomainname/somelocaldomainname
I updated variable to GF_SERVER_ROOT_URL=http://somelocaldomainname
and got possibility to log-in but after that on each page I get Unauthorized.
Removing GF_SERVER_ROOT_URL variable and restarting server didn’t help.
Is it possible to restore access to existed configuration? In grafana.db I see my configured Data source, Dashboards and so on… 
Version of Grafana v5.2.1 (commit: 2040f61)
— Updated —
i’ve turned on log level debug
t=2018-09-04T04:43:28+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/ status=302 remote_addr=10.101.100.12 time_ms=0 size=29 referer=
t=2018-09-04T04:43:28+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/login status=302 remote_addr=10.101.100.12 time_ms=5 size=24 referer=
t=2018-09-04T04:43:28+0000 lvl=dbug msg="Updating last user_seen_at" logger=context userId=1 orgId=1 uname=admin user_id=1
t=2018-09-04T04:43:30+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/dashboards/home status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/
t=2018-09-04T04:43:30+0000 lvl=dbug msg="avatar.fetch(fetch new avatar): http://secure.gravatar.com/avatar/46d229b033af06a191ff2267bca9ae56?d=retro&r=pg&size=200"
t=2018-09-04T04:43:30+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/dashboards/home status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/
t=2018-09-04T04:43:35+0000 lvl=dbug msg="Scheduling update" logger=alerting.scheduler ruleCount=3
t=2018-09-04T04:43:43+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/user status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/profile
t=2018-09-04T04:43:43+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/user/orgs status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/profile
t=2018-09-04T04:43:43+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/user/preferences status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/profile
t=2018-09-04T04:43:43+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/search status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/profile
t=2018-09-04T04:43:43+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/user status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/profile
t=2018-09-04T04:43:44+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/user/orgs status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/profile
t=2018-09-04T04:43:44+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/user/preferences status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/profile
t=2018-09-04T04:43:44+0000 lvl=info msg="Request Completed" logger=context userId=0 orgId=0 uname= method=GET path=/api/search status=401 remote_addr=10.101.100.12 time_ms=0 size=26 referer=http://somelocaldomainname/profile