Thanks for Sunny giving us a feedback.

The issue description

Sunny said:

Hi, i’m using WPvivid with my wordpress site. Everytime I try to backup Database+File (Entire website), it comes to an error saying “wpvivid_request: error (Internal Server Error): an error occurred while preparing the backup. This error could be caused by an unstable internet connection. Please try again later.” 
However, if I only backup Files (excluding database), it works. 
How do I get rid of this error? 

The cause of issue

This error is caused by PHP PDO extension. While backing up entire website including database, It is necessary to enable this extension.

The solution

Please run the following command line to enable PHP PDO extension:

Depending on PHP version, please run the command line below:

php5enmod pdo       for PHP5

phpenmod pdo         for PHP7

Next, depending on your case, you need to restart Apache or Httpd with the following commands :

service apache2 restart         for Apache
service httpd restart               for Httpd

After running the command lines correctly, Backup WordPress Site by WPvivid will be able to backup your site successfully. However, if you are hosting your site on a shared hosting, you need to contact your web host provider to enable PDO extension.