I have a Westell 7500 wireless router at work.
Old A90 modem and linksys wireless router at home.
Made the email server setting changes at home on a desktop, laptop and two iPhones. All worked fine.
Took iPhone and laptop to work. Verizon email wound not work on either. Outlook 2010 reported send/receive failure.
Tried to setup Office desktop with new email server settings: could not do it: the test email would fail every time.
After hours of research and frustration, EUREKA!
The firewall settings on the Westell 7500 were set too high and blocking the ports that Verizon now wants to use for mail.
Changed the firewall setting on the Westell router to "Minimum", clicked Apply and everything immediately worked. The iPhone, the laptop and now I can make the changes to the desktop and it works with the new settings.
So, yes, the router that Verizon supplied, using its recommended settings (Medium for firewall) blocks the ports that Verizon says we must now use for email.
(Note that an alternative solution may be port forwarding the new port values - I did not try this.)