Catalog SEO Configuration and Store View Scope
Check robots specifications and accessibility of the main goal in the current Store View. A deliberately excluded product area is not suitable unchecked as a canonical target.
Compare canonical settings for products and categories in the effective configuration range. A store view can override an inherited value; layered navigation extensions can also bring in their own rules.
Where to check the setting in Magento
Under Stores → Configuration → Catalog → Catalog → Search Engine Optimization, check the canonical specifications for products and categories in the right scope. Also, compare URL rewrites and extensions for layered navigation. A Store View deviation must not be obscured by a global setting.
Example of this specific finding
Illustrative control case: A publicly advertised product variant refers to a main product with noindex. If the main product is to appear in the search, its exclusion contradicts this intention.
follow-up audit in Magento
Compare a product via direct and category path as well as a filter page. Do not force all filter combinations to the same address without checking their contents.
For the main product and variant separately decide which URL should be indexed. Only then canonical and indexing requirements be corrected together.
Derogations and scope
Noindex on the target does not blindly remove: the main product may have been deliberately withdrawn. Another appropriate content or removal of the variant may be required.
Reference: Magento Open Source or Adobe Commerce with classic storefront. Consider store views and extensions; other storefront architectures have their own configurations.
Classify the general error
Definition, system-independent causes and further correction examples: Set indexing intent for both parties