<p>On Mar. 35, I tried to update my site from 3.6.1 to 3.6.3+, and I got the serious problem as shown in the following pic:</p><p><img src="https://moodle.org/pluginfile.php/133/mod_forum/post/1549145/1.png" alt="" width="1341" height="417" role="presentation" class="img-responsive atto_image_button_text-bottom"><br></p><p>If I click "Continue", I will log out and get back to the login page. It seems that I can't do anything more.</p><p>Please help me!</p><p>My site runs on Windows Server 2008 R2, IIS 7.5, MySQL 5.7.21， php7.1.21.</p><p>Thank you.</p>
You can add lines to enable debug output in config.php (which is in the Moodle source code folder).
This should show details of the error which may help you solve the problem, or you can post them here and see if anyone can help.
I got a little progress, but still in trouble.
I rewrite a post here.
Could you have a look?