Check if timeframes is available and fail gracefully otherwise

freqtrade/exchange/exchange.py

@@ -269,6 +269,13 @@ class Exchange(object):
         """
         Checks if ticker interval from config is a supported timeframe on the exchange
         """
+        logger.warning("validate_timerames")
+        if not hasattr(self._api, "timeframes"):
+            # If timeframes is missing, the exchange probably has no fetchOHLCV method.
+            # Therefore we also show that.
+            raise OperationalException(
+                f"This exchange ({self.name}) does not have a `timeframes` attribute and "
+                f"is therefore not supported. fetchOHLCV: {self.exchange_has('fetchOHLCV')}")
         timeframes = self._api.timeframes
         if timeframe not in timeframes:
             raise OperationalException(

freqtrade/resolvers/exchange_resolver.py

@@ -28,6 +28,7 @@ class ExchangeResolver(IResolver):
         except ImportError:
             logger.info(
                 f"No {exchange_name} specific subclass found. Using the generic class instead.")
+        if not hasattr(self, "exchange"):
             self.exchange = Exchange(config)
 
     def _load_exchange(