It seems you might be experiencing a bug with Snapchat where new adds don't show up on the web version but only on mobile. This issue could be related to the proxy settings. Changing proxies might have triggered it in some cases. Unfortunately, there isn't a guaranteed fix for this, but you can try the following steps:
1. Ensure you are using a stable and reliable internet connection.
2. Log out of the account, clear cache and cookies, and log back in.
3. Check the app and device for any pending updates.
4. Contact Snapchat support for further assistance if the issue persists.
Sometimes bugs related to proxies or network settings can be challenging to resolve. If none of the above steps help, reaching out to Snapchat support might be your best bet to get personalized assistance with this issue.