Can't follow from Hubzilla
I tried with two different WP installations with AcitvityPub plugin installed and I am not able to follow from a Hubzilla instance (version 7.6.1 - 1253) - "channel not found". First WP installation in in root directory of a domain, second WP installation is in subdirectory /wp of a domain. There I added the web-finger configuration in .htaccess.
Does the hubzilla instance has the activitypub feature enabled? This seems not be active on all instances I tested so far.
Of course - it federates with Pixelfed and Writefreely without any problems.
Can you send me the server URL and/or your blog url/profile url? Is it a public server so I can create a test account?
Blog URL is https://hiker.tips . Hubzilla server is closed - so I can make you a test account. Any DM to send you user/pw?
btw Would be very grateful if issue #151 could be solved at first - to follow the WP account is possible but the posts in WP are not displayed in the TL of #Pleroma.
Made more test and I found the the plugin works with #Hubzilla. There the connection to the WordPress blog should be added in "Connections - Add" - then it works.