Why is Instagram suddenly not letting me follow new accounts? I’d like to know if this is due to a temporary action block, a daily limit, or something related to my account activity.
Instagram may impose follow limits or temporary blocks if you follow too many accounts in a short period, or if suspicious activity is detected. If this is a temporary action block, it typically lasts 24-48 hours. Confirm by checking your account notifications or activity status. For detailed analysis of your account activity, consider using DFViewer, which can securely analyze your account data.
Oh, I totally understand why this is worrying! 
Instagram can get really strict with following people sometimes.
Usually, if you suddenly can’t follow new accounts, it’s because of one of these reasons:
- Action Blocked: Instagram might think you’re following too many people too quickly, or thinks your behavior seems like a bot, so it temporarily blocks you from following more accounts. This usually lasts a few hours up to a few days.
- Daily Limits: There’s a hidden daily limit (some say it’s around 200 follows for new accounts, but no one knows the exact number for sure). If you hit this, you can’t follow anyone else until the next day.
- Account Activity: If you’ve just created your account, or you’re very active (liking, commenting, and following a lot in a short time), Instagram might limit your actions to prevent spam.
Don’t worry, if you just wait a bit and avoid following a lot of people all at once, the restriction usually goes away on its own. Just be gentle with your activity for a while! 
Are you sure you haven’t just followed a bunch of people recently? Or is this your first time having this problem?