Hi,
Sorry for the delay. This error means that session_start() function doesn’t have write permission to tmp directory on your server. I’m not really sure why this could be happening, but in our plugin newest version 2.7.0 (released today), I’ve added “Session Save Path” option to plugin’s “General” settings tab (in “WooCommerce > Settings > Currency Switcher > General > Advanced Options”). Please try setting it to some writable directory on your server. Also if you wish, you can contact me on [email protected] with your server’s admin access data (WP and FTP), so I could login and check what’s going on.
Best regards,
Tom