Chart showing weird graphs

[Statler]

[{"id":"88cf6203.a189f","type":"ui_chart","z":"48d2a1b1.9516a","name":"","group":"6ff1bfe2.8add3","order":13,"width":18,"height":7,"label":"","chartType":"line","legend":"false","xformat":"HH:mm","interpolate":"bezier","nodata":"","dot":false,"ymin":"10","ymax":"30","removeOlder":"24","removeOlderPoints":"5000","removeOlderUnit":"3600","cutout":0,"useOneColor":false,"colors":["#fdfbfb","#ff0000","#00ff00","#2ca02c","#98df8a","#d62728","#ff9896","#9467bd","#c5b0d5"],"useOldStyle":false,"outputs":1,"x":450,"y":280,"wires":[]},{"id":"6ff1bfe2.8add3","type":"ui_group","z":"","name":"SENSORS","tab":"b36b6083.a19b1","order":3,"disp":true,"width":"18","collapse":false},{"id":"b36b6083.a19b1","type":"ui_tab","z":"","name":"SWITCHES","icon":"dashboard","disabled":false,"hidden":false}]

This chart is never right: Y-axis shows all 0:00 (sometimes) and the values for this specific graph seem to show only the last hour or so. I have no idea what is going wrong because half a year ago it still worked fine.

Any ideas on where to start looking?

[Colin]

Have you updated node red or the dashboard recently? If yes then make sure you are now using the latest. Also clear the browser cache and refresh the page.
Otherwise show us what you are feeding into the chart.

Edit: Also for the future please see this post on how to share flows (and code or logs) here: How to share code or flow json

[Statler]

I have not updated in a while, Colin. But will do it and then reply again. Regarding "on how to share code or flow json": I will do better next time. Actually, I did have a look and thought I did everything correctly. What was wrong in this specific flow?

[Colin]

If you haven't updated then you shouldn't need to, since it was working. However this may be a good opportunity to do it anyway. If you are using an old version of node-red then consider upgrading that too, so you have access to the latest improvements.

[Statler]

Thanks, Colin. I have updated and upgrade nodered and also the dashboard. I did find a smaller issue with the gateway my machine was using and also fixed that. The result is that the charts are working well again. At least it looks like it is all back to normal.

[Colin]

Excellent.