Product Feed fails after a few days

Hey,

I have a question regarding the plugin.
For one of our clients we would like te implement Google Shopping to sell the products and we would like to use your plugin to provide the product feed. While we have great succes with the plugin in other cases, we have run in to a bit of trouble for with this perticular case.

Case:
We have made a setup of the plugin like we always do and after a quick debug the feed is up and running. But after a few days the feed breaks and the shopping ads will stop as a result of this. When you try to view the feed data, all the products are gone, but a red error seems to pop up. (someone deleted the feed, so we can’t post it at this moment.)

Notes:
– We run the free version of the plugin;
– The site has sub-domains in different languages;
– Some product on the site have product variations.

Do you have any idea?

Thank you in advance.