Maximum execution time of 300 seconds exceeded … I got it when uploading more than 15 thousand database rows to phpmyadmin.
I successfully applied this method to resolve the error.
How to solve Fatal Error: Maximum execution time of 300 seconds exceeded in C:\xampp\phpMyAdmin\libraries\classes\Dbi\DbiMysqli.php on line 199 can be solved as below:

1. Look for the config.default.php file in the C:\xampp\phpMyAdmin\libraries directory (xampp directory in windows).
2. Edit the config.default.php file.
3. Search for records where $cfg[‘ExecTimeLimit’] = 300;
4. Add a value of 300 such as 3000 or so, then save.
5. Restart xampp.

Once done, try again to upload the database that previously failed. Good luck.