The problem
When installing a new theme in Appearance > themes > add new, the following message may appear for some users off WordPress:
“The link you followed has expired.”
This message is displayed because your server settings for upload max size or maximum memory are not well configured.
Solution
There is nothing to worry as this is a common issue and very simple to fix.
If you have expertise in setting your server php / memory settings, contact your hosting company to do it for you. They should do it for you quite fast and easily.
Below are the settings that need to be updated:
memory_limit upload_max_size post_max_size upload_max_filesize max_execution_time max_input_time
If you know how to change these settings, you’ll find a detailed documentation here How to fix maximum upload and php memory limit issues in WordPress.
Preferably to the following values.
memory_limit = 256 upload_max_size = 64M post_max_size = 64M upload_max_filesize = 64M max_execution_time = 300 max_input_time = 1000