Hi there,
Woocommerce works fine on its own with fvm, however the theme may be causing issues when you merge js files or css files, or perhaps some other plugin doing optimization as well.
There is info in the faqs about that.
https://wordpress.org/plugins/fast-velocity-minify/#faq
a) You cannot do double minification, so make sure you have disabled any features on your theme or other plugins that perform minification of css, html and js files.
b) If you enabled the option to defer JS or CSS, please note that some themes and plugins need jQuery and other libraries to be render blocking, so they are not “undefined” during page load.
c) The plugin relies on PHP Minify to minify JavaScript and css files, however it is not a perfect library and there are plugins that are already minified and do not output a “min.js” or “min.css” filename (and end up being minified again). Try to disable minification on JS and CSS files and purge the cache, then either dequeue it and enqueue an alternative file or add it to the ignore list.
d) Sometimes a plugin conflicts with another when merged (look at google chrome console log for hints). Try to disable CSS processing first and see if it works. Disable JS processing second and see if it works. Try to disable HTML minification last and see if it works. If one of those work, you know there is a conflict when merging/minifying.
e) If you have a conflict, try to add each CSS and each JS file to the ignore list one by one, until you find the one that causes the conflict. If you have no idea of which files to add, check the log file on the “status page” for a list of files being merged into each generated file.
Alternatively, you could try the autoptimize plugin, or hire a developer to assist you configuring the settings, or do the required fixes so that things won’t break when merging the files.
