Debugging federation issues

I've been trying to subscribe to magazines/communities from lemmy.ca.

I recall seeing on kbin.social that people were having trouble seeing communities from lemmy.ca as well, but it was attributed to the DDoS protections that were enabled. From what I can tell, fedia.io does not seem to have the same protections enabled, but I still cannot see communities from lemmy.ca (e.g. I was able to find [email protected], but not [email protected]).

On lemmy.ca, it seems like fedia.io should be federated with them.

Does anyone have any guidance on how to track down the issue? Thanks in advance!

EDIT: After a few days of trying, I was finally able to discover [email protected], [email protected], and [email protected]. (But [email protected] still doesn't work... Hopefully soon)