diff --git a/lib/kredits.js b/lib/kredits.js
index 73e8641..12d4828 100644
--- a/lib/kredits.js
+++ b/lib/kredits.js
@@ -69,7 +69,10 @@ class Kredits {
     if (wallet) {
       signer = wallet.connect(ethProvider);
     } else if (ethProvider.getSigner) {
-      signer = ethProvider.getSigner();
+      // Only useful for reading data, not writing. The (unused) address is
+      // necessary because without an address, ethers.js will try to look up
+      // the provider's account 0, which doesn't work on our public RSK nodes.
+      signer = ethProvider.getSigner('0xfa77675540E550b911a6AABF3805ac17C6641ec1');
     }
     return new Kredits(ethProvider, signer, kreditsOptions);
   }