diff --git a/dashboard/src/components/AppInstallDialog.vue b/dashboard/src/components/AppInstallDialog.vue
index 5b6867618..4683b6dac 100644
--- a/dashboard/src/components/AppInstallDialog.vue
+++ b/dashboard/src/components/AppInstallDialog.vue
@@ -1,9 +1,9 @@
 <script setup>
 
-import { ref, computed, useTemplateRef, onMounted, inject } from 'vue';
+import { ref, computed, useTemplateRef, onMounted, inject, watch } from 'vue';
 import { marked } from 'marked';
 import { Button, Dialog, SingleSelect, FormGroup, TextInput, InputGroup, Spinner } from '@cloudron/pankow';
-import { prettyDate, prettyBinarySize, isValidDomain } from '@cloudron/pankow/utils';
+import { prettyDate, prettyBinarySize } from '@cloudron/pankow/utils';
 import AccessControl from './AccessControl.vue';
 import PortBindings from './PortBindings.vue';
 import AppsModel from '../models/AppsModel.js';
@@ -39,23 +39,28 @@ const locationInput = useTemplateRef('locationInput');
 const description = computed(() => marked.parse(manifest.value.description || ''));
 const domains = ref([]);
 
-const formValid = computed(() => {
-  if (!domain.value) return false;
+const form = ref(null); // assigned via "Function Ref" because it is inside v-if
+const isFormValid = ref(false);
+async function checkValidity() {
+  isFormValid.value = form.value ? form.value.checkValidity() : false;
 
-  if (location.value && !isValidDomain(location.value + '.' + domain.value)) return false;
+  if (isFormValid.value) {
+    if (accessRestrictionOption.value === ACL_OPTIONS.RESTRICTED && (accessRestrictionAcl.value.users.length === 0 && accessRestrictionAcl.value.groups.length === 0)) {
+      isFormValid.value = true;
+    }
 
-  if (accessRestrictionOption.value === ACL_OPTIONS.RESTRICTED && (accessRestrictionAcl.value.users.length === 0 && accessRestrictionAcl.value.groups.length === 0)) return false;
-
-  if (manifest.value.id === PROXY_APP_ID) {
-    try {
-      new URL(upstreamUri.value);
-      // eslint-disable-next-line no-unused-vars
-    } catch (e) {
-      return false;
+    if (manifest.value.id === PROXY_APP_ID) {
+      try {
+        new URL(upstreamUri.value);
+        // eslint-disable-next-line no-unused-vars
+      } catch (e) {
+        isFormValid.value = false;
+      }
     }
   }
-
-  return true;
+}
+watch(form, () => { // trigger form validation when the ref becomes set
+  setTimeout(checkValidity, 100);
 });
 
 const appMaxCountExceeded = ref(false);
@@ -68,7 +73,9 @@ function setStep(newStep) {
   }
 
   step.value = newStep;
-  if (newStep === STEP.INSTALL) setTimeout(() => locationInput.value.$el.focus(), 500);
+  if (newStep === STEP.INSTALL) {
+    setTimeout(() => locationInput.value.$el.focus(), 500);
+  }
 }
 
 // form data
@@ -91,6 +98,8 @@ function onDomainChange() {
 }
 
 async function onSubmit(overwriteDns) {
+  if (!form.value.reportValidity()) return;
+
   formError.value = {};
   busy.value = true;
 
@@ -309,15 +318,15 @@ defineExpose({
           <div class="error-label" v-if="formError.generic">{{ formError.generic }}</div>
           <div class="error-label" v-if="formError.dnsExists">{{ formError.dnsExists }}</div>
 
-          <form @submit.prevent="onSubmit(false)" autocomplete="off">
+          <form :ref="(el) => { form = el; }" @submit.prevent="onSubmit(false)" autocomplete="off" @input="checkValidity()">
             <fieldset :disabled="busy">
-              <input style="display: none;" type="submit" :disabled="!formValid" />
+              <input style="display: none;" type="submit" :disabled="busy" />
 
               <FormGroup :class="{ 'has-error': formError.location }">
                 <label for="location">{{ $t('appstore.installDialog.location') }}</label>
                 <InputGroup>
                   <TextInput id="location" ref="locationInput" v-model="location" style="flex-grow: 1"/>
-                  <SingleSelect v-model="domain" :options="domains" option-label="label" option-key="domain" @select="onDomainChange()" :search-threshold="10"/>
+                  <SingleSelect v-model="domain" :options="domains" option-label="label" option-key="domain" @select="onDomainChange()" :search-threshold="10" required/>
                 </InputGroup>
                 <div class="warning-label" v-show="domainProvider === 'noop' || domainProvider === 'manual'" v-html="$t('appstore.installDialog.manualWarning', { location: ((location ? location + '.' : '') + domain) })"></div>
                 <div class="error-label" v-if="formError.location">{{ formError.location }}</div>
@@ -328,21 +337,21 @@ defineExpose({
                 <small>{{ port.description }}</small>
                 <InputGroup>
                   <TextInput :id="'secondaryDomainInput' + key" v-model="port.value" :placeholder="$t('appstore.installDialog.locationPlaceholder')" style="flex-grow: 1"/>
-                  <SingleSelect v-model="port.domain" :options="domains" option-label="label" option-key="domain" />
+                  <SingleSelect v-model="port.domain" :options="domains" option-label="label" option-key="domain" required/>
                 </InputGroup>
               </FormGroup>
 
-              <FormGroup :class="{ 'has-error': formError.upstreamUri }" v-show="manifest.id === PROXY_APP_ID">
+              <FormGroup :class="{ 'has-error': formError.upstreamUri }" v-if="manifest.id === PROXY_APP_ID">
                 <label for="upstreamUri">Upstream URI</label>
-                <TextInput id="upstreamUri" v-model="upstreamUri" />
+                <TextInput id="upstreamUri" v-model="upstreamUri" required/>
               </FormGroup>
 
               <PortBindings v-model:tcp="tcpPorts" v-model:udp="udpPorts" :error="formError" :domain-provider="domainProvider"/>
               <AccessControl v-model:option="accessRestrictionOption" v-model:acl="accessRestrictionAcl" :manifest="manifest" :users="users" :groups="groups" :installation="true"/>
 
               <div class="bottom-button-bar">
-                <Button v-if="needsOverwriteDns" danger @click="onSubmit(true)" icon="fa-solid fa-circle-down" :disabled="!formValid" :loading="busy">Install {{ manifest.title }} and overwrite DNS</Button>
-                <Button v-else @click="onSubmit(false)" icon="fa-solid fa-circle-down" :disabled="!formValid" :loading="busy">Install {{ manifest.title }}</Button>
+                <Button v-if="needsOverwriteDns" danger @click="onSubmit(true)" icon="fa-solid fa-circle-down" :disabled="busy || !isFormValid" :loading="busy">Install {{ manifest.title }} and overwrite DNS</Button>
+                <Button v-else @click="onSubmit(false)" icon="fa-solid fa-circle-down" :disabled="busy || !isFormValid" :loading="busy">Install {{ manifest.title }}</Button>
               </div>
             </fieldset>
           </form>
diff --git a/dashboard/src/components/app/Location.vue b/dashboard/src/components/app/Location.vue
index 2b2405a1e..48bd43236 100644
--- a/dashboard/src/components/app/Location.vue
+++ b/dashboard/src/components/app/Location.vue
@@ -82,6 +82,8 @@ function onRemoveRedirect(index) {
 }
 
 async function onSubmit() {
+  if (!form.value.reportValidity()) return;
+
   busy.value = true;
   errorMessage.value = '';
   errorObject.value = {};