diff --git a/src/main/java/info/weboftrust/ldsignatures/signer/LdSigner.java b/src/main/java/info/weboftrust/ldsignatures/signer/LdSigner.java
index 7fd1295..2f8fcb5 100644
--- a/src/main/java/info/weboftrust/ldsignatures/signer/LdSigner.java
+++ b/src/main/java/info/weboftrust/ldsignatures/signer/LdSigner.java
@@ -114,7 +114,7 @@ private void loadMissingContext(JsonLDObject jsonLDObject){
         if(this.getSignatureSuite().getSupportedJsonLDContexts().stream().noneMatch(jsonLDObject.getContexts()::contains)){
             URI missingJsonLDContext = this.signatureSuite.getDefaultSupportedJsonLDContext();
             if (missingJsonLDContext != null) {
-                JsonLDUtils.jsonLdAddAsJsonArray(jsonLDObject, Keywords.CONTEXT, missingJsonLDContext);
+                JsonLDUtils.jsonLdAddAsJsonArray(jsonLDObject, Keywords.CONTEXT, JsonLDUtils.uriToString(missingJsonLDContext));
             }
         }
     }