Rajesh Soni

Have you tried uploading another MP3 file with smaller file size?
Try renaming the MP3 file to something else and then try to upload it.

Try renaming wp-content/plugins to something else, then access the “Pages” section, and try to EDIT an existing page. Send screenshots of any error
Also send a screenshot of the PAGES view while hovering over any existing page, so we can see the action items.

NOTE** While the plugins folder is renamed, do NOT go to the “Plugins” section, as that would disable all active plugins.

After taking screenshots, rename the wp-content/plugins folder back to the original name.

Can you upload a full-page screenshot of the admin section and a snapshot from the wp-content/plugins folder (via FTP or CPanel File manager)?

https://www.tipsandtricks-hq.com/create-a-wordpress-admin-user-for-a-wordpress-site-via-mysql-6649

https://codingcyber.org/change-wordpress-user-role-database-using-phpmyadmin-3390/

https://wordpress.stackexchange.com/questions/64466/making-someone-a-wordpress-administrator-using-phpmyadmin

Is that the only account you have access to?
Are you sure that account has administrator privileges?

Did you try sorting the posts by Published date? Or scrolling back all the way to the end?

OR even try to search for the new post content in the same window.

Screenshot of the entire page with any possible errors?

Do you notice any JavaScript errors in the browser debugging console?

Probably the account you’re logged in as, has NO administrator privileges.

Then try switching to a WordPress default theme. Like “Twenty Seventeen”.

<?php
function text_after_content($content) {

echo "<xmp>content:" . __LINE__ . "\r\n"; var_dump($content); echo "</xmp>"; 
if ( in_category('First') ) {
$content.= "<p>Custom text 1</p>";
}
if ( in_category('Second') ) {
$content.= "<p>Custom text 2</p>";
}
}
return $content;
}
add_filter ('the_content', 'text_after_content');
?>

Great!

Okay, what exactly happens when you try to login as admin?
Does it show an error about invalid username or password or keeps on redirecting or what exactly?

As expected, there’s a JavaScript error that’s causing the issue.

[Show/hide message details.] ReferenceError: WPSetAsThumbnail is not defined[Learn More] media-upload.php:1:1

Try disabling all other plugins.

Please send a full-length screenshot of the error AND the browser debugging console.