I reached out to Boxify and I was sent this message. At least it explains some things. Hope it helps. I am going to reach out to Shopify again.
Yes, I know what’s going on. Shopify has been rolling out a new version of its checkout. And that new version is buggy. It (sometimes) takes a customer who has seen rates offered, selected a shipping option and then entered payment information back into the checkout, showing them a nonsensical error message about shipping options having changed. This affects some checkouts for merchants using shipping apps to display shipping rates at checkout. Why one checkout is affected and another isn’t, nobody knows.
This very same thing happened in late October/early November, affecting some merchants using shipping apps (not just Boxify). It took Shopify at least a week to fix it back then. Now it’s all happening once more with the new checkout code Shopify has been rolling out this past week or so. All to say, it’s a mess–a mess that has happened before in the not-so-distant past.
Shopify’s developers are working to figure this out, but in the meantime the solution is to have your shop put back on the old version of checkout. That’s worked for other affected merchants. The challenge is to get Shopify to do that for you. I’ve been battling with Shopify for more than a week, first just to alert them to the problem, then to try to convince the technical support specialist I’ve been in contact with that Shopify should go ahead and switch all affected merchants back to the old version of checkout–or at least do that for the set of merchants that I explained had experienced these difficulties. This specialist said that each merchant has to individually request help from Shopify.
The problem is that the support reps merchants contact may or may not know what to do. Some merchants have told me that they have had to keep opening new tickets with new support reps until finally they land on one who understands the problem and switches their shop back to the old checkout. So when you contact Shopify support, don’t accept an answer from anyone who tells you that the problem is with Boxify or that you should ask your customers to clear their browser cache or anything like that. The fix, at least for the short term, would be to have your shop put back on the old version of checkout. This is not something you or I can do: Shopify must do it.
What might help would be for you to quote the following snippet from an interaction I had with a Shopify technical support rep named Thomas W.:
I completely understand your frustration with this problem and have been working hard to get this resolved as quickly as we can.
To that end, we have a team of developers currently working on a solution right now. We have also identified a workaround for merchants who come to us with this issue that we have to manually apply to their accounts. If you have any other merchants come to you for assistance with this please have them reach out directly to us and we should be able to resolve this for them right away.