Please post the errors you see in Error Console - control + shift + J

I have no idea whatsoever what the moderator is suggesting!

I have since discovered that my e-mails are visible on my mobile phone in the Plusnet mailbox, but not on my desktop,which is more important to me. They disappeared after I created some new folders in the manage folders section, but as a result, they were not in fact registered finally, that after I transferred e-mails to them, and seemingly they are also lost now. The e-mail provision by Plusnet has caused me a lot of stress and disappointment over the years, so I would be grateful if you could help me with my desktop access.