Alternate Way to Change My Wordpress Login

I'm sorry to hear that you're unable to reset your Wordpress password. The cause for why your Linode isn't sending email could mean a lot of things.

I looked into other possible ways to reset the password, and it looks like the best option if you're in a rush and don't have the time to troubleshoot your mail server would be to manually access the database on your Linode and edit it there. I found this resource on the Wordpress Codex, which works as their Community site. It explains how to reset a password through the Wordpress Command Line tool:

• Resetting Your Wordpress Password

If you don't already have the Wordpress CLI, this page should direct you on how to get this:

• The command line interface for WordPress

In short, you can reset your admin password by ssh to host, and cd into respective wordpress site
wp user reset-password admin

If you have forgotten username, then you can get it by
wp user list

user_login is the username, which should replace admin in reset-password command.

The "Resetting Your WordPress Password" link that @watrick mentioned no longer seems to resolve, but here's the new URL:

Resetting Your Password

This WordPress help page will walk you through changing a user password through the Admin screen, a forgotten password email link, the MySQL command line, phpMyAdmin, FTP, and the WP-CLI.

It is important to note that in an effort to fight spam, Linode restricts outbound connections on ports 25, 465, and 587 on all Linodes for new accounts created after November 5th, 2019.

This means that you may not be able to reset your WordPress password via email. Even if your Linode does not have port restrictions in place, you may still run into mail deliverability issues if you have not correctly setup forward and reverse DNS records as well as SPF records authorizing your Linode to send mail on behalf of your domain.

https://www.linode.com/docs/guides/running-a-mail-server/