The reasons for this situation are that the recruitment information has expired or been deleted, the website has limited functions and the recruitment information is incomplete.

1. The recruitment information has expired or been deleted: if the recruitment information has expired or been deleted, the phone number will also disappear.

2. Website function restriction: Some recruitment websites may not provide the function of displaying telephone numbers, or the display of telephone numbers is restricted for security reasons.

3. Incomplete recruitment information: If the recruitment information is incomplete, including the phone number is not filled in or filled in incorrectly, the phone number will also be invisible.