552 5.1.1 <my>@zoho.com Mailbox delivery failure policy error

552 5.1.1 <my>@zoho.com Mailbox delivery failure policy error

Dear sir/madam,

I use a personal Zoho email account, to which I forward email from another domain. Since about 12 hrs ago, these emails have all been bouncing, with the error message:

552 5.1.1 < brenthuisman@zoho.com> Mailbox delivery failure policy error

I have not changed any configuration on either Zoho or the account that is forwarded to Zoho. What may be the issue and can it be resolved?

Thank you.