diff --git a/core/src/main/java/bisq/core/api/CoreOffersService.java b/core/src/main/java/bisq/core/api/CoreOffersService.java
index 252fe11a7e0..ba1750290fd 100644
--- a/core/src/main/java/bisq/core/api/CoreOffersService.java
+++ b/core/src/main/java/bisq/core/api/CoreOffersService.java
@@ -464,22 +464,35 @@ private OfferPayload getMergedOfferPayload(EditOfferValidator editOfferValidator
         // in OfferPayload.
         Offer offer = openOffer.getOffer();
         String currencyCode = offer.getCurrencyCode();
-        boolean isEditingPrice = editType.equals(FIXED_PRICE_ONLY) || editType.equals(FIXED_PRICE_AND_ACTIVATION_STATE);
-        Price editedPrice;
-        if (isEditingPrice) {
-            editedPrice = Price.valueOf(currencyCode, priceStringToLong(editedPriceAsString, currencyCode));
+        boolean isUsingMktPriceMargin = editOfferValidator.isEditingUseMktPriceMarginFlag.test(offer, editType);
+        boolean isEditingFixedPrice = editType.equals(FIXED_PRICE_ONLY) || editType.equals(FIXED_PRICE_AND_ACTIVATION_STATE);
+        Price editedFixedPrice;
+        if (isEditingFixedPrice) {
+            editedFixedPrice = Price.valueOf(currencyCode, priceStringToLong(editedPriceAsString, currencyCode));
         } else {
-            editedPrice = offer.getPrice();
+            // When isUsingMktPriceMargin=true, (fixed) price must be set to 0 on the server.
+            // The client, however, still must show the calculated price when
+            // isUsingMktPriceMargin=true.
+            editedFixedPrice = isUsingMktPriceMargin ? Price.valueOf(currencyCode, 0) : offer.getPrice();
         }
 
-        boolean isUsingMktPriceMargin = editOfferValidator.isEditingUseMktPriceMarginFlag.test(offer, editType);
+        // If isUsingMktPriceMargin=true, throw exception if new fixed-price != 0.
+        // If isUsingMktPriceMargin=false, throw exception if new fixed-price == 0.
+        if (isUsingMktPriceMargin && editedFixedPrice.getValue() != 0)
+            throw new IllegalStateException(
+                    format("Fixed price on mkt price margin based offer %s must be set to 0 in server.",
+                            offer.getId()));
+        else if (!isUsingMktPriceMargin && editedFixedPrice.getValue() == 0)
+            throw new IllegalStateException(
+                    format("Fixed price on fixed price offer %s cannot be 0.", offer.getId()));
+
         boolean isEditingMktPriceMargin = editOfferValidator.isEditingMktPriceMargin.test(editType);
         double newMarketPriceMargin = isEditingMktPriceMargin
                 ? exactMultiply(editedMarketPriceMargin, 0.01)
                 : offer.getMarketPriceMargin();
 
         MutableOfferPayloadFields mutableOfferPayloadFields = new MutableOfferPayloadFields(
-                Objects.requireNonNull(editedPrice).getValue(),
+                Objects.requireNonNull(editedFixedPrice).getValue(),
                 isUsingMktPriceMargin ? newMarketPriceMargin : 0.00,
                 isUsingMktPriceMargin,
                 offer.getBaseCurrencyCode(),
diff --git a/core/src/main/java/bisq/core/offer/OfferUtil.java b/core/src/main/java/bisq/core/offer/OfferUtil.java
index e93e420f892..488fb87567a 100644
--- a/core/src/main/java/bisq/core/offer/OfferUtil.java
+++ b/core/src/main/java/bisq/core/offer/OfferUtil.java
@@ -420,7 +420,7 @@ public OfferPayload getMergedOfferPayload(OpenOffer openOffer,
                 original.getOwnerNodeAddress(),
                 original.getPubKeyRing(),
                 original.getDirection(),
-                mutableOfferPayloadFields.getPrice(),
+                mutableOfferPayloadFields.getFixedPrice(),
                 mutableOfferPayloadFields.getMarketPriceMargin(),
                 mutableOfferPayloadFields.isUseMarketBasedPrice(),
                 original.getAmount(),
diff --git a/core/src/main/java/bisq/core/offer/bisq_v1/MutableOfferPayloadFields.java b/core/src/main/java/bisq/core/offer/bisq_v1/MutableOfferPayloadFields.java
index e672a2c0ed5..c7e654594f5 100644
--- a/core/src/main/java/bisq/core/offer/bisq_v1/MutableOfferPayloadFields.java
+++ b/core/src/main/java/bisq/core/offer/bisq_v1/MutableOfferPayloadFields.java
@@ -32,7 +32,7 @@
 @Setter
 public final class MutableOfferPayloadFields {
 
-    private final long price;
+    private final long fixedPrice; // Must be 0 when marketPriceMargin = true (on server).
     private final double marketPriceMargin;
     private final boolean useMarketBasedPrice;
     private final String baseCurrencyCode;
@@ -69,7 +69,7 @@ public MutableOfferPayloadFields(OfferPayload offerPayload) {
                 offerPayload.getExtraDataMap());
     }
 
-    public MutableOfferPayloadFields(long price,
+    public MutableOfferPayloadFields(long fixedPrice,
                                      double marketPriceMargin,
                                      boolean useMarketBasedPrice,
                                      String baseCurrencyCode,
@@ -83,7 +83,7 @@ public MutableOfferPayloadFields(long price,
                                      @Nullable String bankId,
                                      @Nullable List<String> acceptedBankIds,
                                      @Nullable Map<String, String> extraDataMap) {
-        this.price = price;
+        this.fixedPrice = fixedPrice;
         this.marketPriceMargin = marketPriceMargin;
         this.useMarketBasedPrice = useMarketBasedPrice;
         this.baseCurrencyCode = baseCurrencyCode;
@@ -102,7 +102,7 @@ public MutableOfferPayloadFields(long price,
     @Override
     public String toString() {
         return "MutableOfferPayloadFields{" + "\n" +
-                "  price=" + price + "\n" +
+                "  fixedPrice=" + fixedPrice + "\n" +
                 ", marketPriceMargin=" + marketPriceMargin + "\n" +
                 ", useMarketBasedPrice=" + useMarketBasedPrice + "\n" +
                 ", baseCurrencyCode='" + baseCurrencyCode + '\'' + "\n" +