@AlCalzone , thank you! I solved the problem.

I think the problem is that iobroker don't have rights to make any changes in /home/iobroker directory,
although I work under root.
I made some subdirectories manually, but it continues to display error messages with other subdirectories.

I think the problem is that iobroker don't have rights to make any changes in /home/iobroker directory,
although I work under root.

I made it. Problem still exists.

Error EACCES: permission denied happens when I try to install adapters.

root@wirenboard-AUCPMJ6J:~# iobroker install mqtt
sudo: unable to resolve host wirenboard-AUCPMJ6J: No such file or directory
NPM version: 6.11.3
npm install iobroker.mqtt@2.0.4 --loglevel error --prefix "/opt/iobroker" (System call)
npm ERR! code EACCES
npm ERR! syscall mkdir
npm ERR! path /home/iobroker
npm ERR! errno -13
npm ERR! Error: EACCES: permission denied, mkdir '/home/iobroker'
npm ERR!  { [Error: EACCES: permission denied, mkdir '/home/iobroker']
npm ERR!   cause:
npm ERR!    { Error: EACCES: permission denied, mkdir '/home/iobroker'
npm ERR!      errno: -13,
npm ERR!      code: 'EACCES',
npm ERR!      syscall: 'mkdir',
npm ERR!      path: '/home/iobroker' },
npm ERR!   isOperational: true,
npm ERR!   stack: 'Error: EACCES: permission denied, mkdir \'/home/iobroker\'',
npm ERR!   errno: -13,
npm ERR!   code: 'EACCES',
npm ERR!   syscall: 'mkdir',
npm ERR!   path: '/home/iobroker' }
npm ERR!
npm ERR! The operation was rejected by your operating system.
npm ERR! It is likely you do not have the permissions to access this file as the current user
npm ERR!
npm ERR! If you believe this might be a permissions issue, please double-check the
npm ERR! permissions of the file and its containing directories, or try running
npm ERR! the command again as root/Administrator.

I've found this topic https://forum.iobroker.net/topic/17206/javascript-adapter-lässt-sich-nicht-mehr-installieren and tried to follow recomendations from it:

sudo chmod 777 /opt/iobroker
sudo chown -R $(whoami) ~/.npm
sudo chown -R $(whoami) ~/.config
sudo chown -R $(whoami) /opt/iobroker

also, as alternative:

sudo chown -R iobroker /opt/iobroker

All was useless.

Could you help to solve the problem?