1. Add to cart button not shown. Why?

Go to Joomla admin - J2Store - Options - Cart settings

Set the Enable Catalog mode to NO.

Catalog mode: E-commerce / cart functions is disabled. The products are shown as a catalog with price.

Also go to your product and make sure that Enable cart feature is set to YES.

2. Do not see J2Store tab in Article edit layout / article manager

Go to Article Manager->Options. Make sure that the Show Article Options parameter in the Editing Layout tab is set to Yes. Only then, you will see the J2Store block while creating an article.

Go to Plugin Manager and make sure that Content - J2Store and System - J2Store plugins are published.

3. Fatal error: Call to undefined function json_last_error()

Your server has PHP 5.2 or lower version. J2Store needs at least PHP 5.3 to operate effectively. Ask your hosting service provider to upgrade to PHP 5.3.x, which is the latest version.

4. Add to cart not working

This problem may happen due to several reasons.

A possible reason is JavaScript conflicts. The JavaScript libraries from other extensions may cause errors. Use the Firebug extension for Firefox to find out which JavaScript library causing the error and ask the concerned extension developer for a solution.

5. Could not delete global product options

If you have associated a product option with one or more products, you cannot delete it. First, you have to go to the products and disassociate them. Then you can delete it.

An easy workaround is: Unpublish the global product option that you want to remove. The unpublished options will not show up on the front end.

6. Could not disable shipping address fields

If you want to disable the shipping address fields, then you have first to set the Shipping Address Fields in Joomla admin->j2store->options->cart settings to Disabled. Then you should always set the Enable shipping for this product (in the product/article form) to No.

7. Administrators are not getting order emails

Check your shop settings tab in Joomla admin->J2store->Options.

You might have set same email address for both the Default 'From' Email address and the admin email. On many occasions, if the 'From' and 'To' addresses are same, servers would flag them as spam or just ignore them to deliver. Try to set a different email for the From Address.
If that is not working, Please use a Gmail address as the Admin Email.

Also,
Please make sure your Joomla website is capable of sending emails.
There are 99 chances out of 100 that your problem comes from your Joomla config.

In your backend, go to Site > System Information > Configuration File and look for the sendmail property. Note it.

Now, go to Site > Global Configuration > Server and make sure that the sendmail path field value matches the value you found in the configuration file.

Also you should make sure:

- make sure your hoster did not block your emails
- make sure your website is able to send emails to users (please create a test account, it will send you an email)
- try to modify the sendmail path: /usr/sbin/sendmail -t

8. Changing default country at the checkout

Go to J2Store - Set up  - Custom fields

Open the Country field and choose your default country. Save.

Open the Zone ID field and choose your default zone. Save.