SMTP plugin

I'm having the weirdest issue with the contact forms 7 plugin on my site erlfootballcoaching.com.

All of a sudden it seems to have stopped sending the email to my designated email address.

So if I submit the form here: https://erlfootballcoaching.com/contact/

I get a green success notification, but the email doesn't send to my email.

I know it's working within the website as I have used Flamingo plugin to confirm the email is being logged.

I've tried 'Contact Forms 7' support, but they weren't very helpful, only suggesting that I deactivate all plugins and reset back to default theme (which will obvs break the site). I'm guessing this was to try troubleshoot, but the only plugin I've added is Yoast SEO ages ago, and was working with that for a fair while till I had this issue.

Weirdly, when I tried using my email address as the notification email, it did actually come through once, but not on any subsequent occasions, which I guess suggests its some weird spam issue maybe? But I have checked junk / spam folders on every email used and can't see anything!

Long story short, I think I need to install an SMTP plugin like WP Easy SMTP and put in some login credentials for a real mailbox so spam/email filters don't intervene. Can someone help me with this please!?