It seems like a relatively new issue: https://github.com/laravel/framework/issues/53721

Which should be fixed in the next release.

In the meantime, you should manually upgrade the symfony/mailer package.

composer require "symfony/mailer:~7.1.0"

If the issue persists try changing the MAIL_ENCRYPTION to

MAIL_ENCRYPTION=tls

As discussed in the issue: https://github.com/laravel/framework/issues/53721#issuecomment-2513369358