Previous year's layer & & & & does not exist

What causes this issue?

To determine the price index via
<GL:index_LIFO_procedure>index LIFO procedure</>, the
<GL:layer>layer</> for the previous period must also be accessed.
In this case, this layer could not be found.

How to fix this error?

Inform your systems administrator.

Error message extract from SAP system. Copyright SAP SE.