Steps to reproduce:
If one enters invalid characters into the host name field for Grafana, different toasties (dependend on the character) will pop up.
Anything but an internal server error toasty.
AFAICT this does only affect the hostname field of the Grafana configuration.
This does affect the host names of other settings, but the toasty will occur later on when one tries to save the page. Also, it's possible to use some characters which do not belong to a host name to store the host name. E.g. "#!".
It is possible