How can I fix the problem with sessions?

I found this in stackoverflow: (Please include it in next release)

In most cases, the real reason of the above errors is the incorrect mechanism for using PHP sessions within plugins or themes when they are using the session_start() function.

Now you need to identify what plugin cause this issue by deactive your plugin one by one.

Then in that plugin, you need to find a piece of code similar to this:

if ( !session_id() ) {
    session_start();
}

then change it to:

if ( !session_id() ) {
    session_start( [
        'read_and_close' => true,
    ] );
}