diff --git a/app/Http/Controllers/RemoteAuthController.php b/app/Http/Controllers/RemoteAuthController.php
index 4b889c933..00bfa397a 100644
--- a/app/Http/Controllers/RemoteAuthController.php
+++ b/app/Http/Controllers/RemoteAuthController.php
@@ -326,6 +326,7 @@ class RemoteAuthController extends Controller
         $token = $request->session()->get('oauth_remote_session_token');
 
         $res = RemoteAuthService::getVerifyCredentials($domain, $token);
+        abort_if(! $res || ! isset($res['acct']), 403, 'Invalid credentials');
         $res['_webfinger'] = strtolower('@'.$res['acct'].'@'.$domain);
         $res['_domain'] = strtolower($domain);
         $request->session()->put('oauth_remasto_id', $res['id']);
diff --git a/app/Services/Account/RemoteAuthService.php b/app/Services/Account/RemoteAuthService.php
index 3e59bf64e..bc9a98ed8 100644
--- a/app/Services/Account/RemoteAuthService.php
+++ b/app/Services/Account/RemoteAuthService.php
@@ -71,14 +71,23 @@ class RemoteAuthService
         }
 
         $url = 'https://'.$domain.'/oauth/token';
-        $res = Http::asForm()->post($url, [
-            'code' => $code,
-            'grant_type' => 'authorization_code',
-            'client_id' => $raw->client_id,
-            'client_secret' => $raw->client_secret,
-            'redirect_uri' => $raw->redirect_uri,
-            'scope' => 'read',
-        ]);
+
+        try {
+            $res = Http::asForm()->timeout(20)->retry(3, 750)->post($url, [
+                'code' => $code,
+                'grant_type' => 'authorization_code',
+                'client_id' => $raw->client_id,
+                'client_secret' => $raw->client_secret,
+                'redirect_uri' => $raw->redirect_uri,
+                'scope' => 'read',
+            ]);
+        } catch (RequestException $e) {
+            return false;
+        } catch (ConnectionException $e) {
+            return false;
+        } catch (\Exception $e) {
+            return false;
+        }
 
         return $res;
     }
@@ -92,7 +101,18 @@ class RemoteAuthService
 
         $url = 'https://'.$domain.'/api/v1/accounts/verify_credentials';
 
-        $res = Http::withToken($code)->get($url);
+        try {
+            $res = Http::withToken($code)->timeout(20)->retry(3, 750)->get($url);
+            if (! $res->ok()) {
+                return false;
+            }
+        } catch (RequestException $e) {
+            return false;
+        } catch (ConnectionException $e) {
+            return false;
+        } catch (\Exception $e) {
+            return false;
+        }
 
         return $res->json();
     }
@@ -108,7 +128,18 @@ class RemoteAuthService
         $key = self::CACHE_KEY.'get-following:code:'.substr($code, 0, 16).substr($code, -5).':domain:'.$domain.':id:'.$id;
 
         return Cache::remember($key, 3600, function () use ($url, $code) {
-            $res = Http::withToken($code)->get($url);
+            try {
+                $res = Http::withToken($code)->timeout(20)->retry(3, 750)->get($url);
+                if (! $res->ok()) {
+                    return false;
+                }
+            } catch (RequestException $e) {
+                return false;
+            } catch (ConnectionException $e) {
+                return false;
+            } catch (\Exception $e) {
+                return false;
+            }
 
             return $res->json();
         });
diff --git a/tests/Feature/RemoteAuthServiceTest.php b/tests/Feature/RemoteAuthServiceTest.php
new file mode 100644
index 000000000..af67195d8
--- /dev/null
+++ b/tests/Feature/RemoteAuthServiceTest.php
@@ -0,0 +1,99 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Models\RemoteAuthInstance;
+use App\Services\Account\RemoteAuthService;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Http\Client\ConnectionException;
+use Illuminate\Support\Facades\Http;
+use PHPUnit\Framework\Attributes\Test;
+use Tests\TestCase;
+
+class RemoteAuthServiceTest extends TestCase
+{
+    use RefreshDatabase;
+
+    private function activeInstance(string $domain = 'mastodon.example'): RemoteAuthInstance
+    {
+        return RemoteAuthInstance::create([
+            'domain' => $domain,
+            'client_id' => 'cid',
+            'client_secret' => 'secret',
+            'redirect_uri' => url('/auth/mastodon/callback'),
+            'active' => true,
+            'banned' => false,
+        ]);
+    }
+
+    #[Test]
+    public function verify_credentials_returns_false_on_connection_failure()
+    {
+        $this->activeInstance();
+
+        Http::fake(function () {
+            throw new ConnectionException('timed out');
+        });
+
+        $res = RemoteAuthService::getVerifyCredentials('mastodon.example', 'token');
+
+        $this->assertFalse($res);
+    }
+
+    #[Test]
+    public function verify_credentials_returns_false_on_server_error()
+    {
+        $this->activeInstance();
+
+        Http::fake([
+            '*' => Http::response('nope', 500),
+        ]);
+
+        $res = RemoteAuthService::getVerifyCredentials('mastodon.example', 'token');
+
+        $this->assertFalse($res);
+    }
+
+    #[Test]
+    public function verify_credentials_returns_json_on_success()
+    {
+        $this->activeInstance();
+
+        Http::fake([
+            '*' => Http::response(['acct' => 'alice', 'id' => '1'], 200),
+        ]);
+
+        $res = RemoteAuthService::getVerifyCredentials('mastodon.example', 'token');
+
+        $this->assertIsArray($res);
+        $this->assertSame('alice', $res['acct']);
+    }
+
+    #[Test]
+    public function get_following_returns_false_on_connection_failure()
+    {
+        $this->activeInstance();
+
+        Http::fake(function () {
+            throw new ConnectionException('timed out');
+        });
+
+        $res = RemoteAuthService::getFollowing('mastodon.example', 'token', 42);
+
+        $this->assertFalse($res);
+    }
+
+    #[Test]
+    public function get_token_returns_false_on_connection_failure()
+    {
+        $this->activeInstance();
+
+        Http::fake(function () {
+            throw new ConnectionException('timed out');
+        });
+
+        $res = RemoteAuthService::getToken('mastodon.example', 'code');
+
+        $this->assertFalse($res);
+    }
+}