Here, we will give some advice on what to do if you get a blank (gray) window without buttons when opening an additional Wazzup chat in Bitrix.
First of all, try logging into your Wazzup account using the same machine and browser via the following link: https://app.wazzup24.com. If everything is fine, it means that the error is caused by your browser which is blocking cookies for embedded windows.
To fix this error, disable the feature blocking third-party cookies. Below are the instructions for Google Chrome, Mozilla Firefox, Opera.
Google Chrome
1. In the upper right corner of the browser, click on the three dots 
→ select “Settings” from the list.
2. Open the “Privacy and Security” tab on the left → select “Third Party Cookies”.
3. Scroll to “Default Settings” → enable “Allow third-party cookies”.
Opera
1. Go to the Settings section.
2. Click the Privacy and Security link in the sidebar.
3. Under “Cookies”, disable the lock.
Mozilla Firefox
1. Select “Content Lock” from the menu.
2. In the Privacy and Security panel, see the settings for blocking content that includes cookies.
3. Select the “Standard” mode: this means that the cookies are not blocked.
