composer install error

[samuelexyz]

[Composer\DependencyResolver\SolverProblemsException]
Problem 1

• The requested package cebe/markdown ~1.1.1 exists as cebe/markdown[1.
  2.x-dev, dev-master] but these are rejected by your constraint.
  Problem 2
• Installation request for yii2mod/yii2-cms * -> satisfiable by yii2mod
  /yii2-cms[dev-master].
• yii2mod/yii2-cms dev-master requires cebe/markdown ~1.1.1 -> no match
  ing package found.
  Potential causes:
  • A typo in the package name
  • The package is not available in a stable-enough version according to you
    r minimum-stability setting
    see https://getcomposer.org/doc/04-schema.md#minimum-stability for mor
    e details.
    Read https://getcomposer.org/doc/articles/troubleshooting.md for further
    common problems.