diff --git a/src/rpc/avalanche.cpp b/src/rpc/avalanche.cpp
--- a/src/rpc/avalanche.cpp
+++ b/src/rpc/avalanche.cpp
@@ -73,6 +73,24 @@
     }
 }
 
+static void verifyProofOrThrow(const NodeContext &node, avalanche::Proof &proof,
+                               const std::string &proofHex) {
+    bilingual_str error;
+    if (!avalanche::Proof::FromHex(proof, proofHex, error)) {
+        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, error.original);
+    }
+
+    avalanche::ProofValidationState state;
+    {
+        LOCK(cs_main);
+        if (!proof.verify(state,
+                          node.chainman->ActiveChainstate().CoinsTip())) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER,
+                               "The proof is invalid: " + state.ToString());
+        }
+    }
+}
+
 static UniValue addavalanchenode(const Config &config,
                                  const JSONRPCRequest &request) {
     RPCHelpMan{
@@ -106,11 +124,8 @@
     CPubKey key = ParsePubKey(request.params[1]);
 
     auto proof = std::make_shared<avalanche::Proof>();
-    bilingual_str error;
-    if (!avalanche::Proof::FromHex(*proof, request.params[2].get_str(),
-                                   error)) {
-        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, error.original);
-    }
+    NodeContext &node = EnsureNodeContext(request.context);
+    verifyProofOrThrow(node, *proof, request.params[2].get_str());
 
     const avalanche::ProofId &proofid = proof->getId();
     if (key != proof->getMaster()) {
@@ -135,10 +150,10 @@
     }
 
     if (!registerProofIfNeeded(proof)) {
-        return false;
+        throw JSONRPCError(RPC_INVALID_PARAMETER,
+                           "The proof has conflicting utxos");
     }
 
-    NodeContext &node = EnsureNodeContext(request.context);
     if (!node.connman->ForNode(nodeid, [&](CNode *pnode) {
             // FIXME This is not thread safe, and might cause issues if the
             // unlikely event the peer sends an avahello message at the same
@@ -150,7 +165,9 @@
             pnode->m_avalanche_state->pubkey = std::move(key);
             return true;
         })) {
-        return false;
+        throw JSONRPCError(RPC_INVALID_PARAMETER,
+                           strprintf("The node does not exist: %d", nodeid));
+        ;
     }
 
     return g_avalanche->withPeerManager([&](avalanche::PeerManager &pm) {
@@ -557,24 +574,6 @@
     return ret;
 }
 
-static void verifyProofOrThrow(const NodeContext &node, avalanche::Proof &proof,
-                               const std::string &proofHex) {
-    bilingual_str error;
-    if (!avalanche::Proof::FromHex(proof, proofHex, error)) {
-        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, error.original);
-    }
-
-    avalanche::ProofValidationState state;
-    {
-        LOCK(cs_main);
-        if (!proof.verify(state,
-                          node.chainman->ActiveChainstate().CoinsTip())) {
-            throw JSONRPCError(RPC_INVALID_PARAMETER,
-                               "The proof is invalid: " + state.ToString());
-        }
-    }
-}
-
 static UniValue sendavalancheproof(const Config &config,
                                    const JSONRPCRequest &request) {
     RPCHelpMan{
diff --git a/test/functional/abc_rpc_addavalanchenode.py b/test/functional/abc_rpc_addavalanchenode.py
--- a/test/functional/abc_rpc_addavalanchenode.py
+++ b/test/functional/abc_rpc_addavalanchenode.py
@@ -55,7 +55,7 @@
         nodeid = add_interface_node(node)
 
         def check_addavalanchenode_error(
-                error_code, error_message, proof=proof, pubkey=proof_master, delegation=None):
+                error_code, error_message, nodeid=nodeid, proof=proof, pubkey=proof_master, delegation=None):
             assert_raises_rpc_error(
                 error_code,
                 error_message,
@@ -75,10 +75,14 @@
                                      proof="f000")
         no_stake = node.buildavalancheproof(
             proof_sequence, proof_expiration, proof_master, [])
-        assert not node.addavalanchenode(nodeid, proof_master, no_stake)
+        check_addavalanchenode_error(-8,
+                                     "The proof is invalid: no-stake",
+                                     proof=no_stake)
 
         self.log.info("Node doesn't exist")
-        assert not node.addavalanchenode(nodeid + 1, proof_master, proof)
+        check_addavalanchenode_error(-8,
+                                     f"The node does not exist: {nodeid + 1}",
+                                     nodeid=nodeid + 1)
 
         self.log.info("Invalid delegation")
         dg_privkey = ECKey()