1) Upgrade to our latest version of the extension.
2) Check the indexing method you are using.
With or without the indexing queue:
Check for any failed jobs in the algoliasearch_queue table.
Check if you use the sku-reindexing form whether an item indexes over.
If you are not using the queue, you may encounter issues with timeouts. We generally recommend using the indexing queue.
With the indexing queue
Ensure you configured the queue correctly using this method. Most issues related to indexing are related to not configuring the indexing queue properly, or due to changes to your indexing queue without re-configuring the indexing queue.
Other common issues relate to third-party extensions adding too many updates to the queue. As a troubleshooting step, disable your extensions and check if the issues with too many queued items still occurs. Find more details on this here.
Make sure that your algolia_queue_runner indexer mode is to set to Update On Save as described here. Recommended set up: