diff --git a/scripts/js/groups-domains.js b/scripts/js/groups-domains.js
index 23adc919..4af046cb 100644
--- a/scripts/js/groups-domains.js
+++ b/scripts/js/groups-domains.js
@@ -611,7 +611,7 @@ function editDomain() {
       "/domains/" +
       newTypestr +
       "/" +
-      encodeURIComponent(domainDecoded),
+      utils.encodePathSegment(domainDecoded),
     method: "put",
     dataType: "json",
     processData: false,
diff --git a/scripts/js/groups.js b/scripts/js/groups.js
index fbad0364..4452466a 100644
--- a/scripts/js/groups.js
+++ b/scripts/js/groups.js
@@ -328,7 +328,7 @@ function editGroup() {
   utils.disableAll();
   utils.showAlert("info", "", "Editing group...", oldName);
   $.ajax({
-    url: document.body.dataset.apiurl + "/groups/" + oldName,
+    url: document.body.dataset.apiurl + "/groups/" + utils.encodePathSegment(oldName),
     method: "put",
     dataType: "json",
     processData: false,
diff --git a/scripts/js/utils.js b/scripts/js/utils.js
index 2ab9edcb..b6554629 100644
--- a/scripts/js/utils.js
+++ b/scripts/js/utils.js
@@ -518,6 +518,13 @@ function parseQueryString() {
   return Object.fromEntries(params.entries());
 }
 
+// Encode a string for use as a URL path segment. encodeURIComponent does not
+// encode dots, but browsers resolve "." and ".." as relative path components
+// before sending the request, breaking domains like "." or "..".
+function encodePathSegment(text) {
+  return encodeURIComponent(text).replaceAll(".", "%2E");
+}
+
 function hexEncode(text) {
   if (typeof text !== "string" || text.length === 0) return "";
 
@@ -726,6 +733,7 @@ globalThis.utils = (function () {
     changeTableButtonStates,
     getCSSval,
     parseQueryString,
+    encodePathSegment,
     hexEncode,
     hexDecode,
     listsAlert,