How to handle delays and greylisting patterns?

What greylisting is:

• Temporary rejection asking sender to retry later
• Spam bots often do not retry
• Legitimate servers do retry

Normal behavior:

• Initial delay (minutes to hours)
• Automatic retry succeeds
• Subsequent emails faster (cached)

When delays are concerning:

• Increasing delay frequency
• New greylisting where none existed
• Combined with other issues

Investigation:

• Check if new IP triggering greylisting
• Verify retry behavior is working
• Consider IP reputation causing increased scrutiny
• Brief inspections are normal. Prolonged delays indicate increased suspicion.