diff --git a/changelog/14551.txt b/changelog/14551.txt
new file mode 100644
index 000000000000..47ef9add25b3
--- /dev/null
+++ b/changelog/14551.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+ui: Fix issue where UI incorrectly handled API errors when mounting backends
+```
\ No newline at end of file
diff --git a/ui/app/adapters/secret-engine.js b/ui/app/adapters/secret-engine.js
index 1d75aae4273d..40edfc3004f3 100644
--- a/ui/app/adapters/secret-engine.js
+++ b/ui/app/adapters/secret-engine.js
@@ -61,15 +61,8 @@ export default ApplicationAdapter.extend({
         data.id = path;
       }
       // first create the engine
-      try {
-        await this.ajax(this.url(path), 'POST', { data });
-      } catch (e) {
-        // if error determine if path duplicate or permissions
-        if (e.httpStatus === 400) {
-          throw new Error('samePath');
-        }
-        throw new Error('mountIssue');
-      }
+      await this.ajax(this.url(path), 'POST', { data });
+
       // second post to config
       try {
         await this.ajax(this.urlForConfig(path), 'POST', { data: configData });
diff --git a/ui/app/components/mount-backend-form.js b/ui/app/components/mount-backend-form.js
index 2433af9bcebb..0493003d97aa 100644
--- a/ui/app/components/mount-backend-form.js
+++ b/ui/app/components/mount-backend-form.js
@@ -113,22 +113,17 @@ export default Component.extend({
         }
       }
 
-      if (!capabilities.get('canUpdate')) {
-        // if there is no sys/mount issue then error is config endpoint.
-        this.flashMessages.warning(
-          'You do not have access to the config endpoint. The secret engine was mounted, but the configuration settings were not saved.'
-        );
-        // remove the config data from the model otherwise it will save it even if the network request failed.
-        [this.mountModel.maxVersions, this.mountModel.casRequired, this.mountModel.deleteVersionAfter] = [
-          0,
-          false,
-          0,
-        ];
-      }
+      let changedAttrKeys = Object.keys(mountModel.changedAttributes());
+      const updatesConfig =
+        mountModel.isV2KV &&
+        (changedAttrKeys.includes('casRequired') ||
+          changedAttrKeys.includes('deleteVersionAfter') ||
+          changedAttrKeys.includes('maxVersions'));
+
       try {
         yield mountModel.save();
       } catch (err) {
-        if (err.message === 'mountIssue') {
+        if (err.httpStatus === 403) {
           this.mountIssue = true;
           this.set('isFormInvalid', this.mountIssue);
           this.flashMessages.danger(
@@ -136,9 +131,31 @@ export default Component.extend({
           );
           return;
         }
-        this.set('errorMessage', 'This mount path already exist.');
+        if (err.errors) {
+          let errors = err.errors.map((e) => {
+            if (typeof e === 'object') return e.title || e.message || JSON.stringify(e);
+            return e;
+          });
+          this.set('errors', errors);
+        } else if (err.message) {
+          this.set('errorMessage', err.message);
+        } else {
+          this.set('errorMessage', 'An error occurred, check the vault logs.');
+        }
         return;
       }
+      if (updatesConfig && !capabilities.get('canUpdate')) {
+        // config error is not thrown from secret-engine adapter, so handling here
+        this.flashMessages.warning(
+          'You do not have access to the config endpoint. The secret engine was mounted, but the configuration settings were not saved.'
+        );
+        // remove the config data from the model otherwise it will save it even if the network request failed.
+        [this.mountModel.maxVersions, this.mountModel.casRequired, this.mountModel.deleteVersionAfter] = [
+          0,
+          false,
+          0,
+        ];
+      }
       let mountType = this.mountType;
       mountType = mountType === 'secret' ? `${mountType}s engine` : `${mountType} method`;
       this.flashMessages.success(`Successfully mounted the ${type} ${mountType} at ${path}.`);
diff --git a/ui/app/templates/components/mount-backend-form.hbs b/ui/app/templates/components/mount-backend-form.hbs
index 58a4c5eaad23..0d9612ca5c59 100644
--- a/ui/app/templates/components/mount-backend-form.hbs
+++ b/ui/app/templates/components/mount-backend-form.hbs
@@ -21,7 +21,7 @@
 <form {{action (perform this.mountBackend) on="submit"}}>
   <div class="box is-sideless is-fullwidth is-marginless">
     <NamespaceReminder @mode="enable" @noun={{if (eq this.mountType "auth") "Auth Method" "Secret Engine"}} />
-    <MessageError @model={{this.model}} @errorMessage={{this.errorMessage}} />
+    <MessageError @model={{this.model}} @errorMessage={{this.errorMessage}} @errors={{this.errors}} />
     {{#if this.showEnable}}
       <FormFieldGroups
         @model={{this.mountModel}}
diff --git a/ui/tests/acceptance/settings/mount-secret-backend-test.js b/ui/tests/acceptance/settings/mount-secret-backend-test.js
index d73eaf746722..2f3cbfe07c48 100644
--- a/ui/tests/acceptance/settings/mount-secret-backend-test.js
+++ b/ui/tests/acceptance/settings/mount-secret-backend-test.js
@@ -89,7 +89,7 @@ module('Acceptance | settings/mount-secret-backend', function (hooks) {
     await page.enableEngine();
     await page.selectType('kv');
     await page.next().path(path).submit();
-    assert.dom('.alert-banner-message-body').hasText('This mount path already exist.');
+    assert.dom('.alert-banner-message-body').containsText(`path is already in use at ${path}`);
     assert.equal(currentRouteName(), 'vault.cluster.settings.mount-secret-backend');
 
     await page.secretList();