This sometimes happens when trying to install the EFIversion of grub to a device when you are booted into Legacy/MBR mode. It doesn't seem to occur on all machines, but some and seems somewhat BIOS dependent.
grub-install --target=x86_64-efi /dev/sda
Installing for x86_64-efi platform.
grub-install.real: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image..
grub-install.real: warning: Couldn't find physica........
Your database uses Antelope as the file format. Full UTF-8 support in MySQL and MariaDB requires the Barracuda file format. Please switch to the Barracuda file format. See the documentation MySQL full unicode support for details.
In /etc/my.cnf under [mysqld]
180827 21:43:14 InnoDB: 5.5.59 started; log sequence number 1589339
180827 21:43:14 [ERROR] /usr/libexec/mysqld: unknown variable 'db_file_format=Ba........
This is often the result of PayPal's "item name" or another name having invalid characters or not supporting Unicode.
173.0.81.1 - - [17/Jul/2018:13:39:45 -0400] "POST //modules/gateways/callback/paypal.php HTTP/1.1" 406 - "-" "PayPal IPN ( https://www.paypal.com/ipn )"
A good clue is if you check the debug output of the IPNand find a mandatory column empty.
........