A few hours before the blocks were continuously zero TX. What could be the reason

A few hours before the blocks were continuously zero TX. What could be the reason.

the waves team will make a statement on this topic

There were few very huge transactions and some small and “weak” nodes couldn’t mine blocks because of the performance issues.
The latest node version (0.16.3) improves the performance of node and in the future, even weak nodes will be able to mine blocks without such problems.