Cannot access marketplace or use any commands when joining someone else's world on Bedrock

I cannot access marketplace or use any commands when joining someone else's world on Bedrock. I keep getting the error "invalid session (try restarting your game)" message. 

When I try to use any command, it throws up an error saying it doesn't exist. 

Also my skin won't load and I can't make any changes to my character. 

I can still play on the other person's world, so it's not an internet issue. I have restarted many times and even uninstalled and reinstalled. 

Other people I know are experiencing the same issues.