MySQL server has gone away in variable_set() (line 999 of /includes/bootstrap.inc).

Hello,

All of a sudden I started getting this error message on /admin/content (I do use admin_views)

Additional

PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in variable_set() (line 999 of /includes/bootstrap.inc).

Uncaught exception thrown in session handler.

PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in _drupal_session_write() (line 209 of includes/session.inc).

When I do a Google search I see tons of results for this error. Any tips? I saw some recommendations that max_allowed_packet may be the culprit for a similar forum post, but it is already set to 16M.