Xbox uses voice chat (party chat). There is no text chat in Roblox on Xbox One. It was removed awhile back.
Roblox on Xbox has an integrated voice chat system that allows you to chat with your friends and party members.
Xbox Live Party Chat. Roblox also allows for the use of Xbox Live Party Chat with your Xbox Live friends. When active, this feature automatically overrides in-game chat. Note: You can switch to in-game chat by going to the "Your party" panel in Xbox and selecting "Switch to game chat".
On top of that, players on Xbox can even add friends through Roblox that may be playing on different devices—resulting in cross platform play. Unfortunately, unlike on PC or mobile, the Xbox version of Roblox doesn't have an easily accessible Add Friend menu.
If a microphone is connected via a headset or Kinect, you are automatically placed into voice chat with other players in the game you joined. Note: Voice communication must be enabled in Xbox Settings. Note: You can switch to in-game chat by going to the "Your party" panel in Xbox and selecting "Switch to game chat".
There is no text chat in Roblox on Xbox One.
The second reason why the can't chat in Roblox error happens is related to the fact that the developers added a default system of settings. As a result, the contact settings are set to “No one” in the privacy section. Changing this setting to everyone will fix the can't chat in Roblox error.
If the person that you are trying to message has a Message button that is not clickable, then their privacy settings might not be set up to allow private messages at this time. Additionally, you will need to make sure your privacy settings would allow them to message you back.
Changing Privacy and Chat SettingsLog into the account. (If you can't log in, try these steps for recovering your password.)Go to account Settings. Browser - find the gear-icon located at the upper-right corner of the site. ... Select the Privacy tab.Adjust the Contact Settings and Other Settings.
Roblox on Xbox has an integrated voice chat system that allows you to chat with your friends and party members.
If a microphone is connected via a headset or Kinect, you are automatically placed into voice chat with other players in the experience you joined.
Roblox also allows for the use of Xbox Live Party Chat with your Xbox Live friends. When active, this feature automatically overrides in-experience chat.