Why isn't my email showing in my inbox?

I have three emails, 2 personal emails through gmail and my student email, which uses outlook. I forward my student email to one of my gmail accounts, as most of the time a response isn’t needed but if I need to reply to an email I log in to my student email.

It’s worked fine, until Friday. I’m still getting the forwarded emails in my gmail account, but they aren’t showing up at all in my actual account when I log in.