diff --git a/electrum/util.py b/electrum/util.py
index c12d271de..d5216027a 100644
--- a/electrum/util.py
+++ b/electrum/util.py
@@ -891,14 +891,10 @@ def age(
 mainnet_block_explorers = {
     '3xpl.com': ('https://3xpl.com/bitcoin/',
                         {'tx': 'transaction/', 'addr': 'address/'}),
-    'Bitupper Explorer': ('https://bitupper.com/en/explorer/bitcoin/',
-                        {'tx': 'transactions/', 'addr': 'addresses/'}),
     'Bitflyer.jp': ('https://chainflyer.bitflyer.jp/',
                         {'tx': 'Transaction/', 'addr': 'Address/'}),
     'Blockchain.info': ('https://blockchain.com/btc/',
                         {'tx': 'tx/', 'addr': 'address/'}),
-    'blockchainbdgpzk.onion': ('https://blockchainbdgpzk.onion/',
-                        {'tx': 'tx/', 'addr': 'address/'}),
     'Blockstream.info': ('https://blockstream.info/',
                         {'tx': 'tx/', 'addr': 'address/'}),
     'Bitaps.com': ('https://btc.bitaps.com/',
@@ -909,8 +905,6 @@ mainnet_block_explorers = {
                         {'tx': 'tx/BTC/', 'addr': 'address/BTC/'}),
     'Insight.is': ('https://insight.bitpay.com/',
                         {'tx': 'tx/', 'addr': 'address/'}),
-    'TradeBlock.com': ('https://tradeblock.com/blockchain/',
-                        {'tx': 'tx/', 'addr': 'address/'}),
     'BlockCypher.com': ('https://live.blockcypher.com/btc/',
                         {'tx': 'tx/', 'addr': 'address/'}),
     'Blockchair.com': ('https://blockchair.com/bitcoin/',
@@ -923,8 +917,6 @@ mainnet_block_explorers = {
                         {'tx': 'tx/', 'addr': 'address/'}),
     'OXT.me': ('https://oxt.me/',
                         {'tx': 'transaction/', 'addr': 'address/'}),
-    'smartbit.com.au': ('https://www.smartbit.com.au/',
-                        {'tx': 'tx/', 'addr': 'address/'}),
     'mynode.local': ('http://mynode.local:3002/',
                         {'tx': 'tx/', 'addr': 'address/'}),
     'system default': ('blockchain:/',