There is no need to explain things to you because by your rank you already knew there is a thread that displays all the bitcoin signature campaign.

There are some things to consider if you applied for a signature campaignand denied

Are you SMAS blacklisted

Are you active on the forum

Do you post good posts at least 65% of your post needs to be quality

If you meet up with these requirements; it could be that you often narrowly missed the new signature campaign announcement.

While waiting for the bitcoin signature campaign, you can try to apply for altcoin signature campaign because they are less strict with a very friendly rules and regulations.