Non-admin User cannot Login > Error: Your role does not give you permission to view this page

First verify that the User License did not exceed the allocated number. To verify this navigate, under the Administrator role, to Setup > Company > View Billing Information > Billable Components > Full Access User and look for the related the columns for the Provisioned Quantity and Currently Used.

Note: The amount on the Currently Used column should not exceed the Provisioned Quantity column. If the license usage has exceeded the current allocation the user either frees-up user license or contact the Account Manager for the purchase of additional licenses. If the license checks out fine proceed with the following troubleshooting steps:

1. Clear the browser's cache.  
2. Use a different browser to login (Chrome,cMozilla Firefox, Safari or Internet Explorer).
3. Reset the user password through the Administrator role:

a. Setup > Users/Roles > Manage Users.
b. Select User.
c. Edit the record.
d. Navigate to Access tab.
e. Set new Password and Confirm Password. 
f. Set Require Password Change On Next Login = T.
g. Save.