Google Chrome:
Step 1:
Go to settings -> Security and Privacy -> Clear Browsing Data
Choose "All Time"
Choose:
browsing
cookies
cached images
Click Clear Data
Step 2:
Go to Cookies and other site data
Scroll down to "Sites that can always use cookies"
Click "add"
Enter the following text
[*.]paychex.com
Click "Add"
Click "Add"
Enter the following text
[*.]centralservers.com
Click "Add"
Step 3:
Reset Google Chrome (X out)
Step 4:
Type into your browser - paychexflex.com
Note: Do not use any bookmarks. Type the web address.