I’ve had the same problem, it broke all our plugins except for weathermaps.
This happened because of an update, and seems to be related to the laravel framework, which librenms uses.
Since I update the code manually every month, and keep a history of the versions we run, I was able to revert this quite easily with git checkout.
I can tell the problem happened between version:
38a638358df8a73154c7f68cb2ec5379aa67294f
which was working perfectly, and
c14fd96bb473cd18ef696a870abf2b54f6e55bb7
that shows the error message you posted, but I cannot specify the version that actually broke the plugin functionality.
This is a temporary fix, and is not ideal since it will probably break again in the next code update.
Any help as to what caused it, wether it will be fixed By LibreNMS, or what needs to change in the plugin’s code would be very apreciated.