I have an issue with Zoho Mail (free plan). I set up mail forwarding for my accounts and in general the forwarding works OK (5 min delay is a bit annoying). However, there is an issue when I send a mail from one account to another within the same domain (for ex.: admin@mydomain.com sends to user@mydomain.com), it simply doesn't forward to the email of destination account. How can this be fixed?

Also, since I mentioned the 5 min delay for forwarding, I would like to ask if there is a way to reduce the delay in a paid account?