The availability and meaning of volume depend on the instrument and data provider. Missing volume does not necessarily mean no trading took place. Some sources show tick volume, which counts price updates rather than executed quantity.
Identify the data type
Read the label and provider information. Executed volume and tick volume describe different things and should not be treated as interchangeable.
Compare like with like
Use the same provider, instrument and interval. Different exchanges can have different activity, while some markets have no single consolidated volume series.
If a volume indicator is unavailable, use supported data and read the provider's documentation rather than interpreting a blank field as a trading signal.
