Subscription-manager command fails with "[Errno 2] No such file or directory: '/var/lib/rhsm/cache/syspurpose.json'"

Issue

• Why does subscription-manager command fails with "[Errno 2] No such file or directory: '/var/lib/rhsm/cache/syspurpose.json'"?
• All Subscription-managers command returns "[Errno 2] No such file or directory: '/var/lib/rhsm/cache/syspurpose.json'"

# subscription-manager register --username xxxxxxxxxx
Traceback (most recent call last):
File "/usr/lib/python3.6/site-packages/syspurpose/files.py", line 362, in get_cached_contents
self.cache_contents = json.load(io.open(self.cache_path, 'r', encoding='utf-8'))
FileNotFoundError: [Errno 2] No such file or directory: '/var/lib/rhsm/cache/syspurpose.json'