Shopify Progammer or Expert

I am looking for someone who can help solve a very frustrating error that keeps occurring when customer stry to finalize their payment. I have a Shopify store that uses a third party shipping application called Ship Station and for the past week or so, customers who have tried to checkout and make a purchase are greeted with an error that reads "Your cart has been updated and the previous shipping rate isn’t valid".

I have checked my Shopify shipping settings and profiles. Re installed and reset the Ship Station account and even reached out to the support teams for each company and even they were not able to figure out the issue.

I am hoping that a Shopify Programmer or an Expert can take a look and find a solution to the issue.