diff --git a/electrum/invoices.py b/electrum/invoices.py
index c7879fc7e..d921a323c 100644
--- a/electrum/invoices.py
+++ b/electrum/invoices.py
@@ -149,6 +149,10 @@ class LNInvoice(Invoice):
 
     __lnaddr = None
 
+    @invoice.validator
+    def check(self, attribute, value):
+        lndecode(value)  # this checks the str can be decoded
+
     @property
     def _lnaddr(self) -> LnAddr:
         if self.__lnaddr is None:
diff --git a/electrum/lnutil.py b/electrum/lnutil.py
index 67af0cf6b..24f3d341e 100644
--- a/electrum/lnutil.py
+++ b/electrum/lnutil.py
@@ -1036,7 +1036,8 @@ def validate_features(features: int) -> None:
         if (1 << fbit) & LN_FEATURES_IMPLEMENTED == 0 and fbit % 2 == 0:
             raise UnknownEvenFeatureBits(fbit)
     if not features.validate_transitive_dependecies():
-        raise IncompatibleOrInsaneFeatures("not all transitive dependencies are set")
+        raise IncompatibleOrInsaneFeatures(f"not all transitive dependencies are set. "
+                                           f"features={features}")
 
 
 def derive_payment_secret_from_payment_preimage(payment_preimage: bytes) -> bytes: