If you can’t find a record for your ancestor by searching for their name, see if the records have been scanned but not indexed yet.
It’s much quicker to scan a record that it is to index it. Indexing requires people to read the names and type them into a database. This is time consuming so millions of records have been scanned without being indexed yet.
Unindexed scans can be found via the online finding aids presented by the archives where the records are kept. See the Digital Resources Netherlands and Belgium for links to online available records.
Another great place to search for scans is FamilySearch. Search for records by country or go to the Catalog and search for the place of interest.