If your Prestashop is in maintenance mode, once an indexing task is launched you will receive an error message.
To see the error, go to Search Engines > Settings > Indices and click on the red error message.
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How To Fix It
In order for Doofinder to index the data feed correctly, you just have to add our IP address to your Prestashop Admin > Configure > Shop Parameters > General > Maintenance and save.
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Our IPs are as follows, depending on the data center in which your store is configured:
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Europe (EU zone): 54.171.4.216
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USA (US zone): 52.2.218.41
Dootip: If you are not sure what your zone is, feel free to authorize both IPs.
Once authorized, your store will be reachable from our server, allowing it to index your catalog.