You have a newline in your .ini file that should not be there. Lines starting with a # or ‘;’ are treated as comments and are ignored, so the lines should look like this:
# If enabled and user is not anonymous, data proxy will add X-Grafana-User header with username into the req$
;send_user_header = true
But you have a newline part way through the comment so it is invalid, like this:
# If enabled and user is not
anonymous, data proxy will add X-Grafana-User header with username into the req$
;send_user_header = true
Remove the newline so the comment is back on one single line starting with ‘#’