It seems that it never reached spamgourmet because the spamgourmet-counter is not updated.
That sums it up. Another provider is the Steward Medical Group patient portal *support* system. I give them my e-mail, they accept it, and .... I never get a response. I call them, I verify the e-mail, they say that they sent a response, and nothing. The same with various online stores. Places that verify your identity in person, or while accepting payments, so they have no need to restrict where response e-mails go.
With a business card place, I placed an order, got the shopping cart e-mail, and thought that was that. Eventually time was running out for a deadline, and I e-mailed them (from my spamgourmet e-mail), and asked them to cancel the order. The order was cancelled, and I never got any response from them. E-mail *to* them obviously worked, and I think they e-mailed a question originally but got no response, suggesting that e-mail *from* them was getting caught in some problem communicating with spamgourmet.
In these cases, the alias is never even created in Spamgourmet, or if it exists, it doesn't decrement the remaining count. In one case, the upsstore address, e-mails stopped arriving in January 2023, with 16 remaining. I verified with them, in person, that the e-mail hadn't been changed in their system, and I did not receive any e-mails from them. I changed my e-mail to something else in July, and behold, I'm getting e-mails from their system again.
There are many services that don't/can't send e-mails to Spamgourmet addresses (any more), and I've been using temporary mail service providers to sign up to them, or even place orders. (Alternatively I can use another permanent webmail provider, like mail 2 world -- which I hope doesn't go offline soon..) I feel like this largely started happening around January 2023, when it started happening the other-way-around with Proton. For things like shopping carts, I haven't been able to get anyone to look at mail server logs - if even these places have their own mail servers. Calling Citi Bank, they won't accept a spamgourmet address - they say, in person, that it says it's "invalid". (I signed up with Citi using an SG address long ago, and around the start of 2023 they started sending me mail, "We sent you an e-mail and it was returned." Or similar.)