diff --git a/src/bitcoinrpc.cpp b/src/bitcoinrpc.cpp
index 0704173e544..829c8ee2d79 100644
--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -796,7 +796,7 @@ void ThreadRPCServer2(void* parg)
     }
     catch(boost::system::system_error &e)
     {
-        strerr = strprintf(_("An error occurred while setting up the RPC port %i for listening on IPv6, falling back to IPv4: %s"), endpoint.port(), e.what());
+        strerr = strprintf(_("An error occurred while setting up the RPC port %u for listening on IPv6, falling back to IPv4: %s"), endpoint.port(), e.what());
     }
 
     try {
diff --git a/src/qt/bitcoinstrings.cpp b/src/qt/bitcoinstrings.cpp
index 53e729727e3..b92a26c4a47 100644
--- a/src/qt/bitcoinstrings.cpp
+++ b/src/qt/bitcoinstrings.cpp
@@ -19,7 +19,7 @@ QT_TRANSLATE_NOOP("bitcoin-core", ""
 "Acceptable ciphers (default: TLSv1+HIGH:!SSLv2:!aNULL:!eNULL:!AH:!3DES:"
 "@STRENGTH)"),
 QT_TRANSLATE_NOOP("bitcoin-core", ""
-"An error occurred while setting up the RPC port %i for listening on IPv6, "
+"An error occurred while setting up the RPC port %u for listening on IPv6, "
 "falling back to IPv4: %s"),
 QT_TRANSLATE_NOOP("bitcoin-core", ""
 "An error occurred while setting up the RPC port %u for listening on IPv4: %s"),