Adding clients

Hi All, 

I am brand new to Teams and have created a Team where I have added my client as a guest (he is external to my company). He can see the Team and the general channel along with the notes made within this channel. 

I have created multiple channels within the Team that we need to work on together but he can not see the channels even though I have set the setting to be shared. I also can not enter his email to share an individual channel as it says his email cant be found. 

Any help on how  I can gain him access to the other channels would be much appreciated