I needed to enable php-soap in directadmin build php.
Locate your php config file:
cd /usr/local/directadmin/custombuild
./build used_configs
Edit your php5 config file: (example)
vim /usr/local/directadmin/custombuild/custom/suphp/configure.php5
Add: (Note that only the last rule has no slash!)
–enable-soap
Save the file and rebuild PHP:
./build php all