Your e-mail is fine.
"Advice" is not a verb.
Student or Learner
I have a problem with a site login.
I want to send an email, e.g.:
I cannot login to my account.
Q1 Is the email appropriate? Any better suggestions?
Q2 Should I use "Please advise/advice/help"?
I would write "log in" (with a space). For me, login is a noun and "to log in" is a verb.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
It will help the person trying to help you if you provide your username and perhaps other information about your account.
I agree on "log in" and on "advise."
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.