php session problem

There has been no problem before, but today suddenly the server session suddenly became useless. . The session cannot be obtained across interfaces. . . Even after refreshing the page, the session is gone. . . There was no problem before and no operations were done. . What’s the reason-

It is a video uploading platform using an open source project. .
The server is lighttpd and nodejs

Thank you

Reply content:

There has been no problem before, but today suddenly the server session suddenly became useless. . The session cannot be obtained across interfaces. . . Even after refreshing the page, the session is gone. . . There was no problem before and no operations were done. . What’s the reason-

It is a video uploading platform using an open source project. .
The server is lighttpd and nodejs

Thank you

• Check if the hard drive space is full

• Check whether session.auto_start of php.ini is turned on

• Has anyone modified the project? Check if session is closed manually?

• We do not rule out the possibility of being attacked

I have never done any projects in these areas