Unable to access Package Share
How you are using package share?
As Gaurav said, access the package share with this URL: http://localhost:4502/crx/packageshare/login.html with proper Adobe ID Credentials.
Hope this helps!!
Check if the url is same as mentioned above.
Try from different browsers (or network) and see if it works?
I am getting HTTP error:500 on logging in
Just confirmed Ratna's correct answer:
Try with different browser or use alternate link
have you tried with Firefox?