504 Gateway Time-out on Update

Joomla 3.9.19

When I attempt to upgrade from 3.9.19 to 3.9.20 I am getting the following error after about 2 – 3 minutes after clicking ‘update’.

504 Gateway Time-out

The server didn’t respond in time.

This is also happening whenever I try to update the Joomla ‘Installer – Install from Web’ plugin.

Any idea why this would be and what I can do to resolve it? Is it an issue on my web server as opposed to Joomla itself?

<IfModule mod_dtimeout.c>
<Files ~ ".php">
SetEnvIf Request_URI "index.php" DynamicTimeout=600
SetEnvIf Request_URI "/administrator/index.php" DynamicTimeout=600
</Files>
</IfModule>