I have a Mac Mini running OSX 10.7.5 and Mac Mail 5.3. After receipt of each email from Verizon about changing my email settings, I did as I was told.
The first time I could not send or receive mail, so I went back to the old settings and everything was fine. The second time, I visited the forum, read all the posts about Apple Mac settings and tried again. I went step-by-step and restarted the machine as recommended. I could receive mail, but not send a test message after 15 minutes. Then I deleted entirely my mail settings, re-entered them as directed. Same thing happened, could receive mail, but I gave up after 20 minutes waiting for a test message to be sent. So, I went back to the old settings and everything works fine.
Yes, I restarted both my computer both times; yes, I carefully checked all the spelling, etc. as recommended in one post.
What makes this more frustrating is that my recently purchased iPhone has all the new Verizon email settings and I have no problem. So, I have a big problem since in addition to my Mac Mini, I also have an old Powerbook running OX 9 and a first gen iPad that may one day lose the ability for me to use Mac Mail. Am I left with having to use another email client because Verizon suggested changes do not play well with some Apple products?