Mailbox frustrations

Hi,

I’ve recent bought an iPad Pro and I’m having difficulty with my mail. I’ve set up my bt account and I can send and receive mail. However I cannot add any new mailboxes. When I try a message appears saying ’unable to create mailbox, the mailbox couldn’t be created on the server’. On my old iPad and on my phone this is simple and no problems. Not sure what the issue is. I assumed my mailboxes from my phone would automatically set up on my iPad.

thanks for any help

G