Cannot save widget "Graph (classic)". Invalid parameter "Graph": cannot be empty

[Hakuna]

Hi,

I am writing to you with a problem after our infrastructure has been updatd form zabbix 6.0 to 6.4..
We are using self hosted zabbix with last week updated version.

I tried to add a new Graph (classic) with source as Simple Graph. I did this like I used to do it before on my dashboard with ICMP ping response time graphs page.
But when I want to "Save changes" error appears:

• Cannot save widget "Graph (classic)". Invalid parameter "Graph": cannot be empty.

So I tried to create a graph with the parameter Source: "Graph" as in the error, but also the same message pops up. In a nutshell: I can't save any new graph with any prameters in my dashboard!
I attempted various ways, but it seems to be some bigger bug.

Any ideas ?
Greetings

[Soe Min]

I think some invalid blank graphs in existing pages. So you need to find these invalid graphs and delete it. Make sure there is no invalid graph on page and click update. It's sloved.