I'd be happy to help you troubleshoot the issue with WeChat H5 sharing cards not displaying titles and thumbnails.
From what you've described, it seems that the sharing card is working fine in your testing environment, but not when deployed online. This suggests that there might be some configuration or setting that's causing the issue.
One possible solution is to configure IP white lists in the WeChat Security Center. According to WeChat's documentation, IP white lists are used to allow specific IP addresses to access certain features or APIs. In this case, it seems that you need to add your server's IP address to the white list in order for the sharing card to work properly.
Here are some steps you can follow to configure IP white lists in the WeChat Security Center:
1. Log in to the WeChat Developer Platform and navigate to the "Security" section.
2. Click on the "IP White List" tab.
3. Add your server's IP address to the list by clicking the "+" button.
4. Make sure to select the correct protocol (HTTP or HTTPS) and port number if necessary.
Once you've added your IP address to the white list, try deploying your H5 page again and see if the sharing card is now displaying titles and thumbnails as expected.
In addition to configuring IP white lists, there are a few other things you can check to troubleshoot this issue:
1. Make sure that your H5 page is properly configured to use WeChat's sharing API. You can refer to WeChat's documentation for more information on how to do this.
2. Check the console logs in your browser or server-side logs to see if there are any error messages related to the sharing card.
3. Verify that your H5 page is being served over HTTPS (SSL/TLS). WeChat requires all H5 pages to be served over HTTPS in order for sharing cards to work properly.
If you're still having trouble after trying these steps, it may be helpful to reach out to WeChat's support team or a WeChat developer community for further assistance.
Here is the relevant code snippet that you mentioned:
```html
```
In this code snippet, we're using WeChat's JavaScript API to create a sharing card with a title, link, and thumbnail image. The `wx.onMenuShareTimeline` method is used to specify the sharing card's properties.
I hope this helps! Let me know if you have any further questions or need more assistance.
