We have WP network/multisite (not sure which it is called now). periodically different sites will be taken offline by some unknown program and marked as spam on the network dashboard - they are highlighted in pink. They do not show a spam in Akismet. There is no spam on the sites. We have no idea why this is happening. Deactivating plugins will not work because we have no idea when it will happen again. It has happened 3 times in the last 6 weeks. Any ideas?