Field name & already exists in dynpro

What causes this issue?

When you insert a block from temporary storage, the fields that have
names are transferred to the screen. If the screen already contains an
element with an identical name, the entire block cannot be inserted.

How to fix this error?

Delete the relevant element in the screen before inserting the block
from temporary storage. You cannot edit the contents of temporary
storage itself.

Error message extract from SAP system. Copyright SAP SE.