diff --git a/src/rpc/client.cpp b/src/rpc/client.cpp
--- a/src/rpc/client.cpp
+++ b/src/rpc/client.cpp
@@ -204,7 +204,7 @@
     UniValue jVal;
     if (!jVal.read(std::string("[") + strVal + std::string("]")) ||
         !jVal.isArray() || jVal.size() != 1) {
-        throw std::runtime_error(std::string("Error parsing JSON:") + strVal);
+        throw std::runtime_error(std::string("Error parsing JSON: ") + strVal);
     }
     return jVal[0];
 }
diff --git a/test/functional/interface_bitcoin_cli.py b/test/functional/interface_bitcoin_cli.py
--- a/test/functional/interface_bitcoin_cli.py
+++ b/test/functional/interface_bitcoin_cli.py
@@ -19,7 +19,7 @@
 BLOCKS = 101
 BALANCE = (BLOCKS - 100) * 50000000
 
-JSON_PARSING_ERROR = 'error: Error parsing JSON:foo'
+JSON_PARSING_ERROR = 'error: Error parsing JSON: foo'
 BLOCKS_VALUE_OF_ZERO = 'error: the first argument (number of blocks to generate, default: 1) must be an integer value greater than zero'
 TOO_MANY_ARGS = 'error: too many arguments (maximum 2 for nblocks and maxtries)'
 WALLET_NOT_LOADED = 'Requested wallet does not exist or is not loaded'