sendMultipleFileMessage can not create thumbnail?

I have a question about using sendMultipleFileMessage.
I can receive a message event onMessageUpdated,

but I can not receive thumbnails

Hello @Moohyun

Welcome to the Sendbird community!

For multiple files message, message.fileInfoList holds thumbnails. Can you check the message you received is instance of MultipleFilesMessage but not FileMessage?

yes it’s in the fileInfoList and message type is MultipleFilesMessage