received the following error when I tried to make a reservation. It has been "freezing" up.

Stack trace:
• line 1327 oflhb\dml\sqlsrv_native_moodle_database.php: dml_sessionwait_exception thrown
• line 593 oflhb\sessionhb.php: call to sqlsrv_native_moodle_database->get_session_lockO
• line ? ofwlicnownfile: call to database_session->handler_readO
• line 184 oflhb\sessionhb.php: call to session_startO
• line 473 oflhb\sessionlib.php: call to session_stub->_ constructO
• line 60 oflhb \sessionhb.php: call to database_session->_ constructO
• line 692 oflhb\setup.php: call to session_get_instanceO
• line 27 of\config.php: call to require_onceO
• line 18 of\blocks\mrbs\web\edit_entry.php: call to require_onceO