title: Microsoft Teams returning error when file is uploaded in bot application using Team's attachment button
body: <p>We have an bot created on bot framework and enabled for Microsoft Teams channel. In the bot, the attachment functionality is enabled and user can send files to bot using Teams and it was working perfectly fine. But from past few week it stops working and uploading file in Team's bot chat is returning error. The attachment functionality is working when file is attached to user's chat and the problem is only coming on bot. It seems the issue is related to Teams client as the uploaded file disappears just after being upload. Please find the screenshot below with error message that appears when the file being uploaded automatically disappears in between. Request to please help with this issue.</p>
  <p><a href="https://i.stack.imgur.com/92mvp.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/92mvp.png" alt="Teams Bot file upload message" /></a></p>