If you've properly created the other accounts, you should be using the following link, wherein you enter your e-mail address and password. Once at the member centre page, click "mail" at the top right. You'll need to do this separately for each e-mail address you created.
I'm not sure if it's possible to do what you want (signing in once) with your three new e-mail addresses. I believe that only works for forwarded e-mails and/or disposable e-mail addresses that are "part of" one of your e-mail addresses.
Of course, rather than using Webmail, you can use an e-mail client like Outlook (on a computer, etc) and create accounts in that e-mail client that would then "go" to all of those accounts and send/receive your e-mails. You would need to create app passwords for each e-mail account in the client.
This should be obvious but it is thwarting me at every turn. I use Win 10 and access Rogers email on my desktop at mail.yahoo.com. I have added two other (non-Rogers/Yahoo) mailboxes to the account and so in the left hand navigation I can switch between my firstname.lastname@example.org mailbox and also see my email@example.com and firstname.lastname@example.org mailboxes. I want to add another ROGERS mail account to the list but cannot seem to do it no matter what I try.
I have access to a second email@example.com account for a NFP organization I volunteer for. If I SIGN OUT of my personal Rogers account and then sign back in as with my NFP credentials, I have full access to the other Rogers account. But if I am in my personal Rogers account, there is no way I can see to just add the second Rogers mailbox credentials.
In settings, under "add mailbox" it tells me I am using 3 of FIFTY available, but unless what I am adding is AOL (who still uses AOL anyway????), Outlook.com, or Google, then there is no option. The only other option is in fact "other" and if I click on that, it tells me I have to go to the Yahoo Mail app on my PHONE to set it up. I HATE the Yahoo mail app for Android and why would I need to go to my phone to set up a connection on my desktop anyway???
I even went so far as to install the Yahoo Mail app on my phone, added the firstname.lastname@example.org account there, and indeed I can now see the separated inboxes of my email@example.com and my firstname.lastname@example.org. But of course it never made any difference on my desktop where I am still not able to simply add the other Rogers.com account to the list of mailboxes whose emails I can see without logging out and logging back in as a different persona.
What am I missing??? Many thanks.
Thank you for posting your email concern in the Community. It would be convenient to check all your email accounts from the Mailboxes feature of the webmail. However, by design, you can only add non-Rogers/Yahoo email accounts.
You can try email client like Outlook to check all your email accounts from one location.
Thanks @RogersMoin . At least that was definitive. Not what I wanted to hear but definitive 😉
Would you care to venture a guess as to WHY Yahoo/Rogers would want to prioritize *other* email providers over its own? I can add up to 50 (!) accounts to be checked under the Yahoo webmail umbrella, but none of them can be Yahoo accounts themselves?