MQTT Data in Grafana using InfluxDB

Hi there,

currently I am working on an IoT Project for my smart home and I am having some problems.

My Setup looks like following:
DHT22 - ESP32 - MQTT - Raspberry PI 4B - NodeRED - Influx DB - Grafana

Everything works except for Grafana.
I think the problem is, that my measurements are transmitted in a string. I have already read several online articles and I tried to use Docker for example, but nothing helped me and I couldnt find a complete tutorial.

The MQTT publish works, I can display my measurements in the terminal, in NodeRED and in Influx if I use “select * from temperature limit 5” for example.

But Grafana alwas shows:
“InfluxDB Error: unsupported mean iterator type: *query.stringInterruptIterator”
when I try to import the data.

I added a screenshot of the working status at the moment.

Please help me on how to get my Data into Grafana and plotting it in 2 different graphs.

Thank you very much!

Greetings from Germany