I’m unclear about the extent here.
Are these issues arising with messages for one recipient, or all recipients?
If all users, your SMTP server (sending) settings are incorrect for your mail provider.
Settings . Passwords & Accounts > select the Verizon mail account > select the account again > scroll down and select the outgoing (SMTP) mail server > select the primary outgoing mail server for the account as the Verizon mail server, and then check the settings for the outgoing mail server. The settings there must match your mail provider settings, and enter your credentials for the Verizon mail server there. It’ll look more or less like this:
![](https://discussions.apple.com/content/attachment/07719513-8621-4787-870b-e22c2294673c)
Here are some settings published by Verizon Wireless:
![](https://discussions.apple.com/content/attachment/fab44aac-ebb9-4a2b-8361-f1cb308c8aba)
Your host name is correct, though you’ll need to use port 465 and SSL/TLS secure connection, and your Verizon.net login.
Based on a quick look at the Verizon setup notes, it seems some folks using the old server were expected to migrate to,either AOL or Yahoo mail.
https://www.verizon.com/support/consumer/email
![](https://discussions.apple.com/content/attachment/c87e85b2-9fe4-41e0-acaf-ce00380afbd0)