Nodes update - SELF_SIGNED_CERT_IN_CHAIN error

Hi All,
trying to update node-red nodes from "Manage palette", I have everytime, for all nodes I try to update, an error that says "err SELF_SIGNED_CERT_IN_CHAIN".

Here below the complete log:

2022-08-18T12:59:23.275Z Install : node-red-contrib-opcua 0.2.285

2022-08-18T12:59:23.319Z npm install --no-audit --no-update-notifier --no-fund --save --save-prefix=~ --production --engine-strict node-red-contrib-opcua@0.2.285
2022-08-18T12:59:41.637Z [err] npm
2022-08-18T12:59:41.641Z [err]  
2022-08-18T12:59:41.642Z [err] ERR!
2022-08-18T12:59:41.643Z [err]  
2022-08-18T12:59:41.644Z [err] code
2022-08-18T12:59:41.645Z [err]  SELF_SIGNED_CERT_IN_CHAIN
2022-08-18T12:59:41.646Z [err] npm
2022-08-18T12:59:41.647Z [err]  
2022-08-18T12:59:41.648Z [err] ERR!
2022-08-18T12:59:41.649Z [err]  
2022-08-18T12:59:41.656Z [err] errno SELF_SIGNED_CERT_IN_CHAIN
2022-08-18T12:59:41.705Z [err] npm
2022-08-18T12:59:41.707Z [err]  
2022-08-18T12:59:41.708Z [err] ERR!
2022-08-18T12:59:41.709Z [err]  request to https://registry.npmjs.org/node-red-contrib-opcua failed, reason: self signed certificate in certificate chain
2022-08-18T12:59:41.769Z [err] 
2022-08-18T12:59:41.771Z [err] npm ERR! A complete log of this run can be found in:
2022-08-18T12:59:41.771Z [err] npm 
2022-08-18T12:59:41.771Z [err] ERR!     /root/.npm/_logs/2022-08-18T12_59_41_716Z-debug.log

Can anyone help me?
Thank you in advance.