PLS-907 cannot load library unit

Package compilation failed on one of our database with error:

PLS-00907 : cannot load library unit schema.package

during compiling some package and this package remain invalid state
Cause:
PL/SQL is unable to find and load a library unit that was previously available. This typically happens when you try to load a unit which references another library unit that is non-existent or invalid.
Solution:

alter system flush shared_pool;

after that package compilation run successfully.