Unable to access PHP Composer: Your requirements could not be resolved to an installable set of packages

Symptoms

• In an attempt to access Plesk > Domains > example.com > PHP Composer the error below is  shown:

  PLESK_ERROR: Your requirements could not be resolved to an installable set of packages.
  Problem 1
  - Root composer.json requires plesk/composer-command-info ~1.0.2 -> satisfiable by plesk/composer-command-info[1.0.2].
  - plesk/composer-command-info 1.0.2 requires composer-plugin-api ^1.1 -> found composer-plugin-api[2.0.0] but it does not match your constraint.

• The composer was unexpectedly updated to 2.0 version:
  

  # composer --version
  Composer version 2.0-dev

Cause

This is a Composer extension bug with the ID #EXTPHPCOMP-122.

Fixed in:

• PHP Composer 1.1.0.

Resolution

Please consider updating your server:

• How to update Plesk extensions

Workaround

If update is not possible for some reason you may try the following