diff --git a/evm/evm-rpc/src/rpc-client.ts b/evm/evm-rpc/src/rpc-client.ts
index b2ef8aff3..e7134436a 100644
--- a/evm/evm-rpc/src/rpc-client.ts
+++ b/evm/evm-rpc/src/rpc-client.ts
@@ -29,6 +29,9 @@ export class EvmRpcClient extends RpcClient {
             if (this.isRpcRateLimitError(err)) {
                 return true
             }
+            if (this.isUpstreamUnavailableError(err)) {
+                return true
+            }
             if (this.isRpcInternalError(err)) {
                 return this.retryInternalServerErrors
             }
@@ -49,6 +52,18 @@ export class EvmRpcClient extends RpcClient {
         )
     }
 
+    isUpstreamUnavailableError(err: RpcError): boolean {
+        // Load-balancing / aggregating providers (e.g. uniblock) report a transient
+        // "service unavailable" error when all of their upstream providers momentarily
+        // fail to fulfill a request. This is an availability problem (the HTTP 503
+        // analog), not a permanent one, so it must be retried rather than crash the
+        // ingestion process.
+        return (
+            err.code === -32503 || // JSON-RPC "service unavailable" code used by aggregating providers
+            /prevented the request from being fulfilled/i.test(err.message)
+        )
+    }
+
     isRpcRateLimitError(err: RpcError): boolean {
         return (
             /rate limit|too many requests/i.test(err.message) ||