diff --git a/electrum/lnworker.py b/electrum/lnworker.py
index eae2ac43a..9b69156a6 100644
--- a/electrum/lnworker.py
+++ b/electrum/lnworker.py
@@ -1809,6 +1809,8 @@ class LNWallet(LNWorker):
         self.logger.info(f"creating bolt11 invoice with routing_hints: {routing_hints}")
         invoice_features = self.features.for_invoice()
         payment_preimage = self.get_preimage(payment_hash)
+        if payment_preimage is None:  # e.g. when export/importing requests between wallets
+            raise Exception("missing preimage for payment_hash")
         amount_btc = amount_msat/Decimal(COIN*1000) if amount_msat else None
         if expiry == 0:
             expiry = LN_EXPIRY_NEVER
diff --git a/electrum/wallet.py b/electrum/wallet.py
index 3ef44d9ba..cd88432e5 100644
--- a/electrum/wallet.py
+++ b/electrum/wallet.py
@@ -1066,13 +1066,14 @@ class Abstract_Wallet(ABC, Logger, EventListener):
         data = read_json_file(path)
         for x in data:
             try:
-                req = Invoice(**x)
+                req = Request(**x)
             except:
                 raise FileImportFailed(_("Invalid invoice format"))
             self.add_payment_request(req, write_to_disk=False)
         self.save_db()
 
     def export_requests(self, path):
+        # note: this does not export preimages for LN bolt11 invoices
         write_json_file(path, list(self._receive_requests.values()))
 
     def import_invoices(self, path):
@@ -1125,7 +1126,7 @@ class Abstract_Wallet(ABC, Logger, EventListener):
             for txout in invoice.get_outputs():
                 self._invoices_from_scriptpubkey_map[txout.scriptpubkey].add(invoice_key)
 
-    def _is_onchain_invoice_paid(self, invoice: Invoice) -> Tuple[bool, Optional[int], Sequence[str]]:
+    def _is_onchain_invoice_paid(self, invoice: BaseInvoice) -> Tuple[bool, Optional[int], Sequence[str]]:
         """Returns whether on-chain invoice/request is satisfied, num confs required txs have,
         and list of relevant TXIDs.
         """
@@ -1161,7 +1162,7 @@ class Abstract_Wallet(ABC, Logger, EventListener):
                     is_paid = False
         return is_paid, conf_needed, list(relevant_txs)
 
-    def is_onchain_invoice_paid(self, invoice: Invoice) -> Tuple[bool, Optional[int]]:
+    def is_onchain_invoice_paid(self, invoice: BaseInvoice) -> Tuple[bool, Optional[int]]:
         is_paid, conf_needed, relevant_txs = self._is_onchain_invoice_paid(invoice)
         return is_paid, conf_needed