Subdomain issue

[m0th]

I'm having problems logging into a forum on my subdomain. I can ping the main domain and the subdomain in these formats:

domain.net
subdomain.info

but

subdomain.domain.net

is not able to resolved, but has always worked until now. Is there a DNS issue?

[m0th]

And of course the moment I post, the subdomain magically works again. :rolleyes: