even though i synced klavyio to shopify the streams don't reach the recipient

Hi @VOLTEItalia,

Thanks for sharing this with us.

1. There could be a number of reasons why an email may not reach a desired recipient. For starters, I recommend checking out the threads below for some potential solutions:

While that speaks to flow sending, you may also be interested to check out our article on campaign skip reasons. 

2. What you’re referring to is known as a double opt-in email. According to Shopify’s documentation, you can adjust the double-opt in setting by clicking Settings > Notifications in your Shopify admin. For any further questions on Shopify functionality, I recommend speaking with their support team.
3. If your email address is already a part of this list, or you have previously received an email from a flow triggered off of the Newsletter list, or passed through the flow triggered off of the Newsletter list when the emails in the flow were not live, you would not receive the email(s) contained in that flow. I hope the solutions proposed in the articles at the beginning of my reply help address this point.
4. Depending on what type of tracking you’re referring to, we have documentation on UTM tracking. If you’re referring to tracking numbers as a part of an order, I recommend using our pre-built Shopify Shipping Confirmation flow which will automatically contain tracking information about the order. For more information on using pre-built flows in Klaviyo, see our guide here.

I hope that’s helpful.