Thank you !
Right, I checked four addresses at the end of my subscribers list and whois tells me that all those four different IP addresses are registered with Microsoft. I have no idea why a microsoft IP adress would initiate a request to unsubscribe an email adress from an independent hosting company ? That is so weird…
But thanks again !
PS those IPs were 4.204.211.53, 52.138.177.89, 13.79.152.119, 52.236.180.47.
PPS: is there a ‘bulk’ way to inspect those logs ?