Unsubscribing automatically

Hi there,

On one of my client websites, users are being unsubscribed automatically. Here’s the email from my client:

don’t know why but my email is being unsubscribed from the newsletter. I am not unsubscribing.

I do open the email when I get it but I don’t unsubscribe.

It happened in the previous mailout and I resubscribed myself. It’s just happened again today

Any ideas?

This seems to be a similar issue to this user’s: https://ww.wp.xz.cn/support/topic/users-are-unsubscribing-automatically/

Thanks.