1. ** Check the network connection * *: First of all, you need to confirm whether your network connection is normal. If there is a problem with the network, the link of cow fast transmission may be invalid.

2. ** Re-upload the file and regenerate the link * *: If the link of Cow Fast Pass is invalid, you can try to re-upload the file and regenerate the link, and then share the new link with those who need it.

The above steps are for reference only. If you have any more specific questions, please contact the official customer service of Cow Express directly for consultation.