If you can, you are best to set up the email on the tablet manually rather than using a wizard.
When setting it up you need to decide if you want to use IMAP or POP. Once you have decided use the settings in this link. Make sure that you enter your username and password in both the incoming and outgoing servers. If it is offered, don't use the option "use same as incoming". You may have to enter your full email address ie. email@example.com in the username, not just the prefix ie xxxx before the @btinternet.com.
Server incoming and out going: mail.btinternet.com
Email user name: (Normally you only need the prefix of your email address but some users have found the need to enter their full email address.ie firstname.lastname@example.org)
Password: Your BT email password.
Log on using clear text authentication
Out Going Server in requires Authentication (Use same as incoming mail server. Some users have found that they need to enter the password and username instead of ticking box “use same as incoming mail server” )
Outgoing Port : 465 SSL security
Incoming Port : 995 SSL security
Same as above except for Incoming Port: 993 SSL security