Trying to unsubscribe emails I'm getting from a website; request causes mail to stop working

Kykx wrote:

A window opens that says Mail will send a message from “(null)” to unsubscribe from this mailing list and offers me the options of OK or CANCEL and neither button works and mail stop working as well. I've closed out mail and re-opened it but the problem persists. Any suggestions? Thank you!!

Yes, you wait until Apple resolves the issue check status here Apple - Support - System Status