What must an EU declaration of conformity contain?

At a minimum: the manufacturer with address, an unambiguous product designation, all legal acts applied, the harmonised standards used, the notified body with its identification number where applicable, and place, date and signature with the signatory's function.

Check the list of legal acts in particular. A declaration that covers only electromagnetic compatibility and radio is incomplete for a machine – machinery legislation must also be named.

Also worth checking: does the declaration cover exactly the model and variant you are procuring? And is a person established in the EU named for the technical documentation?

The complete checklist is in guide to CE conformity.