Grafana 502 bad gateway

Hello

I am coming to you because since 2 days I am trouble with grafana
Indeed, when I want to connect to grafana I have a error message “502 bad gateway”.

I have rebooted several my Home Assistant

Here my configuration
Home Assistant on raspberry 4-1go with SD card 32go
System HassOS 3.13
is this issue come of my material or come server grafana or other ?
thank you for help me

And Sorry for my English…