Store ID vs. Influencer ID
EverySqueeze needs your Amazon Store ID, not your Influencer ID — they're different Amazon programs.
These are not the same thing, and mixing them up is the most common Amazon setup mistake.
Store ID (what EverySqueeze needs)
Your Store ID is the tracking ID EverySqueeze uses for every link it builds. In Amazon Associates Central (affiliate-program.amazon.com), click your account name at the top right, then Manage Tracking IDs; it looks like yourname-20. Enter it in Amazon tracking IDs.
Influencer ID (a different program)
Your Influencer ID starts with ONAMZ and belongs to Amazon's Live/Storefront side, not the off-site affiliate links EverySqueeze builds. A link built with it would never earn a commission on the platforms EverySqueeze posts to, so EverySqueeze never suggests one and refuses to save one, with a note saying which ID to use instead. Your storefront link (amazon.com/shop/yourname) is not an ID either; pasting it shows a note explaining the difference.
If you're not sure which you have
Check affiliate-program.amazon.com directly rather than guessing from a saved value elsewhere — an ID that starts with letters other than "onamz" and ends in a short suffix like -20 is almost always the Store ID EverySqueeze wants. Dots and underscores in it are fine (your.name-20). See Which Amazon account do I need?.