I find WP a help and a hindrance at times. It’s a pretty good platform, albeit a little slow and bloated so I try and keep the plugins few and far between. I recently found I couldn’t upload pictures via the WordPress app, and got an error of “The corresponding HMAC for this file does not match”. After some googling, it would appear this is because of the max upload file size. I tried a couple of different routes to fix this, firstly .htaccess file, secondly wp_config.php updating, using a plugin. None worked.
The easiest way I found was simply to create a file called php.ini in your /wp_admin/ with these two lines in it:
upload_max_filesize = 32M
post_max_size = 32M