You are sorting through your business e-mail when you run across a message from an unsatisfied customer unable to purchase one of your products. When she tried adding the product to her shopping cart, she got an error message that said something like: ‘Parameter Missing or Invalid‘.
“What’s that all about?”, you wonder out loud.
What it’s all about is a problem encountered by Shopify because some parameter defining the product in question is incorrect. Your store cannot process the request because of this improperly defined parameter. Fixing it is a matter of figuring out the troubling parameter and correcting it. According to the Shopify manual, there are three possibilities, as explained below.
1. Missing Drop-Down Menu or Radio Button
When you enter products into your Shopify store, you have an opportunity to include multiple variants. With those variants come drop-down menus or radio buttons that enable your customers to choose which variant product they want. But what if you have only one variant?
Some Shopify users will eliminate the drop-down menu or radio button for aesthetic purposes. What they do not know is that Shopify doesn’t like that. It is looking for that field in order to process the order. Eliminating it causes the error. The solution is to replace the drop-down menu or radio button with a substitute that will satisfy the need for a variant ID. If you don’t know how to do that, you can log on to the Shopify community forum and ask for help.
2. Lack of the Default Option
Store owners who choose to use radio buttons for variants have to set a default option. If no default is established and the customer does not make a choice, the field created for the radio button has no data to pass on. It creates the same sort of problem as a missing drop-down menu or radio button.
The solution here is to create a default option. That option will be checked on the user’s page unless he or she chooses another option instead. Data from the form will be passed on to Shopify, and the order will be processed with the default.
3. Improper HTML Code
HTML code is terribly sensitive not only in the commands and tags used but also in the syntax of those commands and tags. Just one little snippet of improperly formatted code could easily generate the ‘Parameter Missing or Invalid’ error. If you check the other two possibilities and you are fairly sure neither one is the culprit, the next step is to validate your code.
There are plenty of free and open-source validation packages available online. Web-based utilities allow you to simply enter the URL of the page in question and click a button to submit. The tool will hunt down the page and validate its code. If you don’t want to do it online, you can look for an off-line tool that will accept a cut and pasted version of your code for validation.