Not receiving Gmail confirmation email to send emails as Zoho account from Gmail

Not receiving Gmail confirmation email to send emails as Zoho account from Gmail

Hello!

I'm having an issue with the "Send mail as" option on Gmail. I am not receiving the confirmation email on my Zoho Mail account. A few days ago, it worked, then it stopped, and now when I try to fix it, I simply don't receive the confirmation email to finish the process. Just to clarify, Gmail can send the email to other Gmail accounts, but I never receive it on Zoho account...

What's going wrong? Is it Zoho's fault? Gmail's? It it my settings?