Unable to place order for this ISIN. Invalid `quantity`

While making redeem of all units of MF it is giving me error.

Unable to place order for this ISIN. Invalid quantity

Request you to raise ticket at support.zerodha.com

In case if you are doing SIP in ELSS/Tax saving fund, you can redeem only the units that were purchased 3 years back as they have lock in period. Just a guess. If your fund is not ELSS/tax saving, log a ticket at support.zerodha.com