diff --git a/freqtrade/data/history.py b/freqtrade/data/history.py
index aff9f5c74..1d1cec65b 100644
--- a/freqtrade/data/history.py
+++ b/freqtrade/data/history.py
@@ -128,9 +128,9 @@ def load_pair_history(pair: str,
                                       drop_incomplete=drop_incomplete)
     else:
         logger.warning(
-            f'No history data for pair: "{pair}", interval: {ticker_interval}. '
-            'Use --refresh-pairs-cached option or `freqtrade download-data` '
-            'script to download the data'
+            f'No history data for pair: "{pair}", interval: {ticker_interval}, in {datadir}. '
+            'Provide the correct path to datadir in config.json, or download data with '
+            '--refresh-pairs-cached option or `freqtrade download-data`. '
         )
         return None
 
diff --git a/freqtrade/plot/plot_utils.py b/freqtrade/plot/plot_utils.py
index 507e86d9d..e132ee2e4 100644
--- a/freqtrade/plot/plot_utils.py
+++ b/freqtrade/plot/plot_utils.py
@@ -9,10 +9,10 @@ def start_plot_dataframe(args: Namespace) -> None:
     Entrypoint for dataframe plotting
     """
     # Import here to avoid errors if plot-dependencies are not installed.
-    from freqtrade.plot.plotting import analyse_and_plot_pairs
+    from freqtrade.plot.plotting import load_and_plot_trades
     config = setup_utils_configuration(args, RunMode.PLOT)
 
-    analyse_and_plot_pairs(config)
+    load_and_plot_trades(config)
 
 
 def start_plot_profit(args: Namespace) -> None:
diff --git a/freqtrade/plot/plotting.py b/freqtrade/plot/plotting.py
index b0b8e3df9..313c2e6d9 100644
--- a/freqtrade/plot/plotting.py
+++ b/freqtrade/plot/plotting.py
@@ -3,7 +3,7 @@ from pathlib import Path
 from typing import Any, Dict, List
 
 import pandas as pd
-
+from freqtrade import OperationalException
 from freqtrade.configuration import TimeRange
 from freqtrade.data import history
 from freqtrade.data.btanalysis import (combine_tickers_with_mean,
@@ -33,9 +33,13 @@ def init_plotscript(config):
         pairs = config["pairs"]
     else:
         pairs = config["exchange"]["pair_whitelist"]
+    if pairs is None:
+        raise OperationalException('No pairs available in config.')
 
     # Set timerange to use
     timerange = TimeRange.parse_timerange(config.get("timerange"))
+    if timerange is None:
+        raise OperationalException('Could not parse timerange in config.')
 
     tickers = history.load_data(
         datadir=Path(str(config.get("datadir"))),
@@ -43,11 +47,15 @@ def init_plotscript(config):
         ticker_interval=config.get('ticker_interval', '5m'),
         timerange=timerange,
     )
+    if tickers is None:
+        raise OperationalException('No ticker data available as specified in config.')
 
     trades = load_trades(config['trade_source'],
                          db_url=config.get('db_url'),
                          exportfilename=config.get('exportfilename'),
                          )
+    if trades is None:
+        raise OperationalException('No trades available as specified in config.')
 
     return {"tickers": tickers,
             "trades": trades,
@@ -324,7 +332,7 @@ def store_plot_file(fig, filename: str, directory: Path, auto_open: bool = False
     logger.info(f"Stored plot as {_filename}")
 
 
-def analyse_and_plot_pairs(config: Dict[str, Any]):
+def load_and_plot_trades(config: Dict[str, Any]):
     """
     From configuration provided
     - Initializes plot-script
@@ -339,7 +347,7 @@ def analyse_and_plot_pairs(config: Dict[str, Any]):
 
     plot_elements = init_plotscript(config)
     trades = plot_elements['trades']
-
+    
     pair_counter = 0
     for pair, data in plot_elements["tickers"].items():
         pair_counter += 1
diff --git a/freqtrade/resolvers/strategy_resolver.py b/freqtrade/resolvers/strategy_resolver.py
index 514e9f22b..2d8b4dca6 100644
--- a/freqtrade/resolvers/strategy_resolver.py
+++ b/freqtrade/resolvers/strategy_resolver.py
@@ -24,8 +24,6 @@ class StrategyResolver(IResolver):
     This class contains all the logic to load custom strategy class
     """
 
-    __slots__ = ['strategy']
-
     def __init__(self, config: Optional[Dict] = None) -> None:
         """
         Load the custom class from config parameter
diff --git a/freqtrade/tests/test_plotting.py b/freqtrade/tests/test_plotting.py
index df208d4d2..6936a8a76 100644
--- a/freqtrade/tests/test_plotting.py
+++ b/freqtrade/tests/test_plotting.py
@@ -30,7 +30,7 @@ def find_trace_in_fig_data(data, search_string: str):
     return next(matches)
 
 
-def generage_empty_figure():
+def generate_empty_figure():
     return make_subplots(
         rows=3,
         cols=1,
@@ -71,7 +71,7 @@ def test_add_indicators(default_conf, caplog):
     # Generate buy/sell signals and indicators
     strat = DefaultStrategy(default_conf)
     data = strat.analyze_ticker(data, {'pair': pair})
-    fig = generage_empty_figure()
+    fig = generate_empty_figure()
 
     # Row 1
     fig1 = add_indicators(fig=deepcopy(fig), row=1, indicators=indicators1, data=data)
@@ -93,7 +93,7 @@ def test_add_indicators(default_conf, caplog):
 
 
 def test_plot_trades(caplog):
-    fig1 = generage_empty_figure()
+    fig1 = generate_empty_figure()
     # nothing happens when no trades are available
     fig = plot_trades(fig1, None)
     assert fig == fig1
@@ -209,7 +209,7 @@ def test_generate_Plot_filename():
 
 
 def test_generate_plot_file(mocker, caplog):
-    fig = generage_empty_figure()
+    fig = generate_empty_figure()
     plot_mock = mocker.patch("freqtrade.plot.plotting.plot", MagicMock())
     store_plot_file(fig, filename="freqtrade-plot-UNITTEST_BTC-5m.html",
                     directory=Path("user_data/plots"))
@@ -229,7 +229,7 @@ def test_add_profit():
 
     df = history.load_pair_history(pair="POWR/BTC", ticker_interval='5m',
                                    datadir=None, timerange=timerange)
-    fig = generage_empty_figure()
+    fig = generate_empty_figure()
 
     cum_profits = create_cum_profit(df.set_index('date'),
                                     bt_data[bt_data["pair"] == 'POWR/BTC'],