Thumbnails are missing, when video or image shared in message.

After upgraded to 10.1.6 - thumbnails are missing, when video or image shared in message body.

Console error: Failed to load resource: the server responded with a status of 400 (Bad Request) 

Any ideas how to get it fixed?

1. Login into Community

2. Go to Group gallery and select video or image

3. Click More link 

4. Click Share link in the appeared popup

5. Add recipient

6. Click Send button