In your screenshots it looks like the ad links to the beap domain but that does not mean that it comes from the beap domain. You may be misinterpreting what you are seeing. The key points to check are:
- Is Pi-hole the only DNS server on your network? Your debug log will help confirm that. Pi-hole staff will look at it when they can.
- Is IPv6 involved in any way which might create a workaround?
If you go to the mail page and load it and then go to your Query Log and inspect it and you see that the beap domain is indeed blocked, that confirms that Pi-hole is working as expected. This means the adverts are coming from a different domain or via a different route which is not blocked. You can use the Query Log to track that down and Blacklist it with the button at the end of the row. This FAQ can also help with that.