Panel error "required parametere"


I didn’t change anything to my website since some month. I tried yesterday to add new pages from my panel. I can connect correctly to the pan but when I try to go anywhere from the panel home page, I get this error : “Required parameter $model follows optional parameter $fields”

So I can’t do anything from my panel.

I noticed that on the panel home page I have a message saying that I don’t have an active Kirby licence. I don’t know if it can be linked to my problem.
I checked the config.php file and there is my key in it, so I don’t understand why I get this message.
I bought a licence in 2018. I still have the email so I re-copy-paste the licence but it don’t change anything.

Can somebody help me please ?