Sharing a topic using FB messenger works fine. I think only custom home page causes such problem. I've not tried categories page yet.
topic thumbnail doesn't show on facebook share
This is what the facebook debugger says.
The provided 'og:image' properties are not yet available because new images are processed asynchronously. To ensure shares of new URLs include an image, specify the dimensions using 'og:image:width' and 'og:image:height' tags. Learn More
Looks like we need to add those to our header.
Where file location i can fix it