Requirements problem

OK
Web serverApache
OK
PHP7.3.21
OK
PHP register globalsDisabled
OK
PHP extensionsEnabled
OK
Database supportEnabled
OK
PHP memory limit128M
OK
File systemWritable (public download method)
OK
Unicode libraryPHP Mbstring Extension
Warning
PHP memory limit128M
Consider increasing your PHP memory limit to 196M to help prevent errors in the installation process. Increase the memory limit by editing the memory_limit parameter in the file /mnt/www/site-php/umndl01/php.ini and then restart your web server (or contact your system administrator or hosting provider for assistance). See the Drupal requirements for more information.
OK
Settings fileThe ./sites/default/settings.php file exists.
Error
Settings fileThe settings file is not writable.
The Panopoly installer requires write permissions to ./sites/default/settings.php during the installation process. If you are unsure how to grant file permissions, consult the online handbook.
Check the error messages and proceed with the installation.