Upgrading from 7.10.7 to 7.11.2: 503 Service Unavailable

Upgrading from 7.10.7 to 7.11.2 using Upgrade Wizard
Upgrade ran well and it took a few minutes on “Upgrade Summary In Progress”
Then it redirected to a blank page with 503 Service Unavailable:

Service Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

Attached the screenshots…

upgradeWizard.log:

Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/ClientTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/RegisteredNamespaceTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/YamlRunnerTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/ConnectionPool/Selectors/RoundRobinSelectorTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/ConnectionPool/Selectors/StickyRoundRobinSelectorTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/ConnectionPool/SniffingConnectionPoolIntegrationTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/ConnectionPool/SniffingConnectionPoolTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/ConnectionPool/StaticConnectionPoolIntegrationTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/ConnectionPool/StaticConnectionPoolTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/Endpoints/AbstractEndpointTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/Endpoints/StatusEndpointTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/Helper/Iterators/SearchResponseIteratorTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/Serializers/ArrayToJSONSerializerTest.php
Thu, 28 Feb 2019 17:25:18 -0500 [UpgradeWizard] - vendor/elasticsearch/elasticsearch/tests/Elasticsearch/Tests/Serializers/EverythingToJSONSerializerTest.php
Thu, 28 Feb 2019 17:25:57 -0500 [UpgradeWizard] - Cleaning up the session. Goodbye.
Thu, 28 Feb 2019 17:25:57 -0500 [UpgradeWizard] - at unlinkUWTempFiles()
Thu, 28 Feb 2019 17:28:40 -0500 [UpgradeWizard] - finished!
Thu, 28 Feb 2019 17:28:40 -0500 [UpgradeWizard] - Cleaning up the session. Goodbye.
Thu, 28 Feb 2019 17:28:40 -0500 [UpgradeWizard] - resetting $_SESSION

CRM Login now shows a blank page…

Some files missing in composer… and tried an upgrade to 7.10.14, and it worked fine.