What is the meaning of "closed period" in "funds purchased during the subscription period generally have to go through a closed period before they can be redeemed"?

Closed period is a stage that must be experienced in the operation of open-end funds.

This time is usually 1-3 months. Closed-end refers to the subscription and redemption of closed-end funds, that is, they cannot be bought or sold.

During this period, the fund opened positions, that is, the raised funds were used for securities trading.

According to the investment direction and the proportion of each direction in the fund prospectus.

After the closure period, the Fund will be open for normal subscription and redemption.