question

I have some productIds that I'm getting from the Finding API and I want to get the name of the product that they correspond to. For some of the productIDs the api returns a Failure response "No match found for your query. Please specify a broader query." but if I lookup the product in the browser by visiting ebay.com/p/PRODUCT_ID eg. http://ebay.com/p/110681406 all of these products exist. What's more, I've had productIds that have failed then half an hour later they suddenly start working again and returning product details. An example request:

http://open.api.ebay.com/shopping?callname=FindProducts
&responseencoding=XML
&appid=MY_APP_ID
&siteid=3
&version=525
&ProductID.type=Reference
&ProductID.Value=110681406
&MaxEntries=1

And the response:

<FindProductsResponse xmlns="urn:ebay:apis:eBLBaseComponents">
<Timestamp>2016-03-06T21:22:39.438Z</Timestamp>
<Ack>Failure</Ack>
<Errors>
<ShortMessage>No match found.</ShortMessage>
<LongMessage>
No match found for your query. Please specify a broader query.
</LongMessage>
<ErrorCode>10.20</ErrorCode>
<SeverityCode>Error</SeverityCode>
<ErrorParameters ParamID="0">
<Value>totalNumMatchingProducts is zero</Value>
</ErrorParameters>
<ErrorClassification>RequestError</ErrorClassification>
</Errors>
<Build>E957_CORE_APILW2_17860840_R1</Build>
<Version>957</Version>
</FindProductsResponse>

Whats going on?