This problem has been there since the Getty web site moved to AWS hosting. The security provided by the service thinks there is some kind of SQL injection happening with a few of the queries and blocks them. It is only tripped when functions such as group_concat() are used.
There are workarounds, if you are interested, although we realize that many people use the sample queries to begin learning SPARQL and the Vocabularies Linked Data implementation. First of all, you can run the queries using an HTTP POST method rather than the GET method the query form uses:
curl -X POST --data-binary 'query=select ?x ?id ?gvpLabel ?prefNl (group_concat(?alt; separator="| ")as?altNl) ?noteNl{ ?x gvp:broaderExtended aat:300209261; dc:identifier ?id; gvp:prefLabelGVP [xl:literalForm ?gvpLabel]. optional{?x xl:pfreflabel [dct:language gvp_lang:nl;xl:literalForm ?prefNl]} optional{?x xl:altlabel [dct:language gvp_lang:nl; xl:literalForm ?alt]} optional{?x xl:skos:scopeNote [dct:language gvp_lang:nl; rdf:value ?noteNI]} } group by ?x ?id ?gvpLabel ?prefNl ?noteNl'
http://vocab.getty.edu/sparql.json
Or, you could simplify the query by taking out the group_concat() function that is making the blocking happen:
select ?x ?id ?gvpLabel ?prefNl ?noteNl{
} group by ?x ?id ?gvpLabel ?prefNl ?noteNl
Hopefully we can solve the blocking issue soon. We are sorry for the inconvenience.
Gregg Garcia
Getty Digital