1: Common failure. The user fails to retrieve a member list of the channel.
GET_MEMBERS_ERR_NOT_IN_CHANNEL: = 5
5: The user is not in the channel.
GET_MEMBERS_ERR_REJECTED: = 2
2: RESERVED FOR FUTURE USE
GET_MEMBERS_ERR_TIMEOUT: = 3
3: A timeout occurs when retrieving a member list of the channel. The current timeout is set as five seconds. The current login timeout is set as six seconds. Possible reasons: The user is in the ABORTED or RECONNECTING state.
GET_MEMBERS_ERR_TOO_OFTEN: = 4
4: The method call frequency exceeds the limit of five calls every two seconds.
GET_MEMBERS_ERR_USER_NOT_LOGGED_IN: = 102
102: The user does not call the login method, or the method call of login does not succeed before retrieving a member list.