# X_ENTITY_SERIES_INVALID

## Means

a time series asked for something no bucket can answer

## Typical cause

an unknown unit, an on column that is not a timestamp(), a zone that is not IANA, or more buckets than one statement answers

## Fix

`posts.series({ on: 'createdAt', unit: 'day', timeZone: 'Europe/Berlin', value: 'count' }) — a listed unit, a timestamp() column, an IANA zone, a range under the bucket ceiling`

[Entity and database](/error-codes#entity-and-database)