The mempool looking empty is not an error though, it is simply showing what the default node actually sees, which means that transactions which have been dropped by default nodes will not show up here.
Maybe higher
maxmempool is a good idea since it's a Blockexplorer nonetheless.
About 2x or 3x the default,
maxmempool=1200?
Not all nodes use the default so sooner or later when the average size goes lower,
those dropped transactions will eventually get propagated again as long as its not past their mempoolexpiry.
In this regard, it's more desirable for a blockexplorer to keep those transactions than follow the default behavior.