Informz has a process that checks email addresses for things like unnecessary tags, characters, spaces, and punctuation. We also cross-reference the address with industry-standard email suppression lists and apply our suppression rule.
If the email addresses were manually uploaded, you can see which were removed and corrected.
Navigate to Subscribers > Upload > Upload History.
Tip: Click Columns to add and remove columns to customize your view.
This process removes "bad" email addresses and corrects email address issues that could cause harm to your deliverability and sender reputation.