Delayed e-mail forwarding

Delayed e-mail forwarding

Hello,

I switched from Google Apps to Zoho Mail, finally managed to set up aliases, catchall e-mail and forwarding, and all seems to work fine except that e-mail forwarding generates unpredictable, somewhat long delays. Incoming e-mails don't get forwarded immediately, but after a while: yesterday the delay was in the 1-5 minutes range; this morning as I'm writing I've been waiting for a forward for 16 minutes and counting.
Is this a know, recurrent issue? Does it happen for forwarded e-mails to get lost?