diff --git a/src/fontra_rcjk/client_async.py b/src/fontra_rcjk/client_async.py
index 998155c..dd14713 100644
--- a/src/fontra_rcjk/client_async.py
+++ b/src/fontra_rcjk/client_async.py
@@ -1,6 +1,5 @@
 import asyncio
 import logging
-from collections import defaultdict
 from contextlib import asynccontextmanager
 
 import aiohttp
@@ -10,11 +9,12 @@
 
 logger = logging.getLogger(__name__)
 
-MAX_CONCURRENT_CALLS = 140  # MySQL's default max connections is 151
+MAX_CONCURRENT_CALLS = 60  # Per client connection
 
 
 class ConcurrentCallLimiter:
-    def __init__(self):
+    def __init__(self, label):
+        self.label = label
         self.num_calls_in_progress = 0
         self.event_queue = []
 
@@ -22,7 +22,7 @@ def __init__(self):
     async def limit(self):
         if self.num_calls_in_progress >= MAX_CONCURRENT_CALLS:
             if not self.event_queue:
-                logger.info("limiting concurrent API calls")
+                logger.info(f"limiting concurrent API calls ({self.label})")
             event = asyncio.Event()
             self.event_queue.append(event)
             await event.wait()
@@ -36,10 +36,7 @@ async def limit(self):
                 event = self.event_queue.pop(0)
                 event.set()
                 if not self.event_queue:
-                    logger.info("done limiting concurrent API calls")
-
-
-call_limiters = defaultdict(ConcurrentCallLimiter)
+                    logger.info(f"done limiting concurrent API calls ({self.label})")
 
 
 class RCJKClientAsync(RCJKClient):
@@ -49,7 +46,7 @@ def _connect(self):
         pass
 
     async def connect(self):
-        self._call_limiter = call_limiters[self._host]
+        self._call_limiter = ConcurrentCallLimiter(self._username)
         self._session = aiohttp.ClientSession(connector=aiohttp.TCPConnector(ssl=False))
         session = await self._session.__aenter__()
         assert session is self._session