[nQSError: 22040] To use AGO function, the storage level of the query ('[time1.time_key]') must be a static level. (HY000)

This error may occurs most probably due to improper Time dimension hierarchy.

To use AGO or TODATE time series functions, it is recommended that, we should define the detailed level also in the Time dimension hierarchy.

Eg : Suppose you have a time dimension table, that includes columns Time_key, Date_value, Month, Quarter, and Year. And If you have created the Time dimension hierarchy with the levels such as YEAR, QUARTER and Month only (there is no level defined for the column Date_value, which describes the granularity (level of detail)of the row.).

• This works fine, for drill down, level based measures and to define aggregate tables. 
• But when you try to use AGO or TODATE function with this Time dimension hierarchy, you will get the above mentioned error.

Solution : Just include one more logical level for the Time dimension hierarchy and add the date_value(or a column which holds granularity for the row.) as a logical key.