diff --git a/src/main/java/uniresolver/driver/did/dns/DidDnsDriver.java b/src/main/java/uniresolver/driver/did/dns/DidDnsDriver.java
index 02789e0..acb1dfd 100644
--- a/src/main/java/uniresolver/driver/did/dns/DidDnsDriver.java
+++ b/src/main/java/uniresolver/driver/did/dns/DidDnsDriver.java
@@ -15,6 +15,7 @@
 import java.util.*;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
 public class DidDnsDriver implements Driver {
 
@@ -129,7 +130,7 @@ public ResolveDataModelResult resolve(DID did, Map<String, Object> resolveOption
 			DIDDocument didKeyDidDocument = this.getClientUniResolver().resolve(target).getDidDocument();
 			if (log.isDebugEnabled()) log.debug("Resolved " + target + " to " + didKeyDidDocument);
 
-			contexts.addAll(didKeyDidDocument.getContexts());
+			contexts.addAll(didKeyDidDocument.getContexts().stream().filter(Objects::nonNull).collect(Collectors.toList()));
 			if (log.isDebugEnabled()) log.debug("Contexts now: " + contexts);
 
 			List<Object> verificationMethods = JsonLDUtils.jsonLdGetJsonArray(didKeyDidDocument.getJsonObject(), DIDKeywords.JSONLD_TERM_VERIFICATIONMETHOD);