How to configure the whitelist in Yahoo! Mail
Yahoo! Mail (on laptop or computer)
Yahoo! Mail App (on cell phone or tablet)
Tap the hamburger menu (three stacked lines) in the top left.
Tap Settings and scroll down to Filters.
Select the email account you want to add a filter for.
Tap the + icon to add a new filter.
Name it anything you want (such as “Whitelist”)
Add the @ihmexico.com
Click the ✓ icon in the top right to save the filter.
Adapted from: https://sumo.com/stories/whitelist