"Extension server error: Operation failed: Permission denied", source: devtools://devtools/bundled/extensions/extensions.js

When running my developing electron.js app, I get indefintely this error message:

“Extension server error: Operation failed: Permission denied”, source: devtools://devtools/bundled/extensions/extensions.js

(base) marco@pc01:~/webMatters/electronMatters/react-ggc$ yarn electron .
yarn run v1.22.5
warning ../package.json: No license field
$ /home/marco/webMatters/electronMatters/react-ggc/node_modules/.bin/electron .
Electron could not be found. No hard resets for you!
(node:12146) ExtensionLoadWarning: Warnings loading extension at /home/marco/.config/react-    
ggc/extensions/fmkadmapgofadopljbjfkapdkoienihi: Cannot load extension with file or directory name 
_metadata. Filenames starting with "_" are reserved for use by the system. 
Added Extension:  React Developer Tools
[12146:0928/102232.427040:ERROR:CONSOLE(216)] "Extension server error: Operation failed:       
Permission denied", source: devtools://devtools/bundled/extensions/extensions.js (216)
[12146:0928/102232.427288:ERROR:CONSOLE(216)] "Extension server error: Operation failed:  
Permission denied", source: devtools://devtools/bundled/extensions/extensions.js (216)
[12146:0928/102233.428075:ERROR:CONSOLE(216)] "Extension server error: Operation failed: 
Permission denied", source: devtools://devtools/bundled/extensions/extensions.js (216)
[12146:0928/102234.427614:ERROR:CONSOLE(216)] "Extension server error: Operation failed:
Permission denied", source: devtools://devtools/bundled/extensions/extensions.js (216)
[12146:0928/102235.428037:ERROR:CONSOLE(216)] "Extension server error: Operation failed: 
Permission denied", source: devtools://devtools/bundled/extensions/extensions.js (216)
[12146:0928/102236.427099:ERROR:CONSOLE(216)] "Extension server error: Operation failed:    
Permission denied", source: devtools://devtools/bundled/extensions/extensions.js (216)
[12146:0928/102237.427452:ERROR:CONSOLE(216)] "Extension server error: Operation failed: 
Permission denied", source: devtools://devtools/bundled/extensions/extensions.js (216)

What does it mean? How to solve it?

Looking forward to your kind help