I’ve run into this issue a few times usually when trying to upload a WordPress theme into a newly created WordPress instance. I figured it’s probably a good time to document it incase someone else is having the same issue.
Although the error message says “The link you followed has expired.”, the root cause is actually your upload being larger than your WordPress instance file size. An easy well to identify your Max upload file size in WordPress is to go to Media -> Add New from the left side nav menu.
Then you’ll see your Maximum upload file size. Usually a default instance is 2 MB
I’ve increased mine to 2 GB as you can see in the screenshot below.
This setting comes from your PHP configuration. If you’re using cPanel, you can simply go to your MultiPHP INI Editor, and increase the post_max_size, and upload_max_filesize to something to something reasonable for the size of files you’ll expect to be uploading in your instance. I chose 2 GB, only because I plan on migrated a large file onto this WP instance, and once it’s done I’ll move it back down to 25 MB.
You can also update your php.ini file
Updating the two lines of code below.
upload_max_filesize = 2048M
post_max_size = 2048M
After that you should be able to upload your theme without an issue.