Error: dynamodb attribute does not exist

A missing non-key attribute is valid in DynamoDB; items do not need identical fields. “Attribute does not exist” may come from application code, a mapper, a failed condition, or a nested update path. Identify which operation raised it before modifying the item.

• Inspect the item by its full primary key. Remove a read ProjectionExpression temporarily, and check whether a GSI projects the requested field.
• Use attribute_not_exists(#field) to test absence. A stored NULL value and an empty string both count as existing attributes.
• Use SET #field = :value to add a top-level field, or SET #field = if_not_exists(#field, :value) to supply a default.
• A nested update such as SET #profile.#city = :city fails if the parent map does not exist. Initialize the map with appropriate concurrency protection, or set the complete map when replacing it is intended.

UpdateItem can also create an item if the key is absent. Add an existence condition when the operation must update an existing record only. Avoid a replacement PutItem merely to add one field: it can remove existing attributes not included in the replacement.

See updating attributes and AWS documentation.