email invoice error: Class 'XMLWriter' not found

Self-hosting installed via zip on AWS Linux instance.

When attempting to email an invoice, I receive the following error in the laravel-error.log:
production.ERROR: Symfony\Component\Debug\Exception\FatalErrorException [1] : /var/www/html/ninja/vendor/sabre/xml/lib/Writer.php [Line 31] => Class 'XMLWriter' not found {"context":"PHP","user_id":1,"account_id":1,

On a potentially related note: when using the download invoice option, I get the following error in the browser: Exporting to ZIP requires the GMP extension. The GMP extension is installed (see below). I’ve checked directory ownership and permissions among many other suggestions.

Any assistance with this would be much appreciated.

PHP has all the required dependencies as follows:

[PHP Modules]
bz2
calendar
Core
ctype
curl
date
dom
exif
fileinfo
filter
ftp
gd
gettext
gmp
hash
iconv
json
libxml
mbstring
mysqli
mysqlnd
openssl
pcntl
pcre
PDO
pdo_mysql
pdo_sqlite
Phar
readline
Reflection
session
SimpleXML
sockets
SPL
sqlite3
standard
tokenizer
wddx
xml
xmlreader
xmlwriter
xsl
zip
zlib

Have you tried yum install php-xml

That was tried and did not fix the issue. I ended up reinstalling on Ubuntu and everything is working fine now.