The best way I've found to increase an opt-in email list size is via a website splash page. Here's a how-to video series to get one setup for your clients or yourself. We've seen huge list growth with our clients. If you need any help setting this up for yourself, email me at firstname.lastname@example.org.
Step 1: Create a Privy.com Account. Use code: TRY50 to save 50% off your first 3 months of a paid account (Click to create an account)
Step 2: Connect Privy.com with Constant Contact
Step 3: Create a Privy Splash Page Offer or Incentive to Join Your List
Step 4: Setup an Autoresponder in Constant Contact (optional)
Step 5: Add Your New Privy Splash Page to Your Website
Step 6: Review Your Splash Page Results and Improve
Thanks for watching. If you need any help or ideas to get your splash page up and running email me at email@example.com.
Thank you for sharing this screenshot! It definitely helps us to understand exactly what you're experiencing. Is this sign-up form on your website? If so, what is the link? Also did you adjust any of the inline code provided for this form? I apologize you're having this experience but we are happy to troubleshoot this further for you.