How to debug Mailgun log error (not receiving activation email)

Spam Cannibal says “bulk emailer not eligible for removal”. Does this mean I have to move from DigitalOcean or Mailgun?

SORBS shows the following:

Summary information for 209.61.151.224/32
Note: Times shown are for the latest entry only!
Found 3 network entries and 0 host/domain entries.

Problem Entries, (listings will cause email problems.)
10 “Spam” entries [20:39:16 29 May 2016 GMT+00].
1 “Escalated” entries [02:09:59 21 Mar 2009 GMT+00].

Usage classification (only important if you run your own mailserver.)
Note: Active “exDUHL” entries mean that the IP/Network has been unblocked for some or all IPs from the DUHL.

Problem hostnames/domains (could cause email problems.)
1 “Spamvertised” entries [10:31:33 28 Oct 2015 GMT+00].
Note:These entries are for URLs or email domains, the IPs that may show up as ‘spamvertised’ only indicate where the URL/Host was seen being sent from. Listings for IPs that are ‘spamvertised’ will not usually cause blocking problems unless the email contains the IP address as a URL
Note: For a more detailed view you have to be registered and logged in.

Current Listings (active)
Historical Listings (inactive)
Current Listing with an active exception
Current Listing however, listings of these types can help mail delivery rather than cause blocking.