1, the lid seal is damaged: the role of the lid seal is to prevent steam leakage, such as the seal is damaged or deformed, will lead to steam leakage, and can not correctly lock the lid.

2, lid handle damage: lid handle is used to fix the lid of the key components, such as handle damage or loose, can not effectively lock the lid.

3. Damage to the internal parts of the lid: the internal parts of the lid, such as pressure valves or seals, such as damage or failure, will affect the normal locking of the lid.