diff --git a/src/core/lib/IP.mjs b/src/core/lib/IP.mjs
index 63816d82..c97f87ab 100644
--- a/src/core/lib/IP.mjs
+++ b/src/core/lib/IP.mjs
@@ -26,7 +26,7 @@ export function ipv4CidrRange(cidr, includeNetworkInfo, enumerateAddresses, allo
     let output = "";
 
     if (cidrRange < 0 || cidrRange > 31) {
-        return "IPv4 CIDR must be less than 32";
+        throw new OperationError("IPv4 CIDR must be less than 32");
     }
 
     const mask = ~(0xFFFFFFFF >>> cidrRange),
@@ -211,7 +211,7 @@ export function ipv4ListedRange(match, includeNetworkInfo, enumerateAddresses, a
         const network = strToIpv4(ipv4CidrList[i].split("/")[0]);
         const cidrRange = parseInt(ipv4CidrList[i].split("/")[1], 10);
         if (cidrRange < 0 || cidrRange > 31) {
-            return "IPv4 CIDR must be less than 32";
+            throw new OperationError("IPv4 CIDR must be less than 32");
         }
         const mask = ~(0xFFFFFFFF >>> cidrRange),
             cidrIp1 = network & mask,
diff --git a/src/core/operations/RegularExpression.mjs b/src/core/operations/RegularExpression.mjs
index 5327870b..5239e55f 100644
--- a/src/core/operations/RegularExpression.mjs
+++ b/src/core/operations/RegularExpression.mjs
@@ -163,7 +163,7 @@ class RegularExpression extends Operation {
                     case "List matches with capture groups":
                         return Utils.escapeHtml(regexList(input, regex, displayTotal, true, true));
                     default:
-                        return "Error: Invalid output format";
+                        throw new OperationError("Error: Invalid output format");
                 }
             } catch (err) {
                 throw new OperationError("Invalid regex. Details: " + err.message);