Plusnet email credentials for adding account to Gmail - not working

[#1]

If anyone can help I'll be grateful.  I would like to add my Plusnet email to Gmail app and, somehow, the system seems to have changed.  My previous Plusnet Credentials don't seem to work and when I add my account (same details as on previous occasions) the only thing which is added is ? The Postmaster account with all emails about bills - not my 'regular' Plusnet inbox and sent emails etc.

I have entered the same credentials as previously but the problem seems to be my user name.  I previously entered username e.g. cjxxxxxxxx+christina but now can only enter username cjxxxxxxxx.  

Any help will be appreciated to get the 'right' Plusnet email reinstated to the Gmail app.  There is no problem with Thunderbird - just the Gmail app on my tablet and mobile.  I have removed the ? Postmaster one and would like to get 'back' to seeing my 'normal' Plusnet emails.

[#2]

I'm sorry I don't know how to edit a post and this post is following on from my post about Plusnet credentials not being accepted when trying to add Plusnet email to the Gmail app on my Tablet and Mobille 'phone.  I telephoned Plusnet first thing this morning and it sounds as if there is a problem with my user name not being accepted when trying to add my 'regular Plusnet email' to the app.  It only seems to be accepting the 'Postmaster' one.

It is going to be referred to Plusnet's Email Team and they will get back to me.  If, in the meantime, anyone else has had a similar difficulty, I'll be pleased to know how it was resolved, thank you.

(I think I can see how to edit a post now.)

[#3]

There is no problem with Thunderbird - just the Gmail app on my tablet and mobile. 

@Crimson that would tend to indicate it's not a problem at the Plusnet end.

I have entered the same credentials as previously but the problem seems to be my user name.  I previously entered username e.g. cjxxxxxxxx+christina but now can only enter username cjxxxxxxxx.  

The username+mailboxname is the correct format for a secondary mailbox, which it sounds like you are trying to access. Using just username accesses the primary (postmaster) mailbox as you have discovered.

One thing to note, for a secondary mailbox, the password is the one that is configured for the mailbox and may be different to the main account one.