Без пароля нельзя войти в аккаунт.

Because без always requires the genitive case.

• Dictionary form: пароль
• Genitive singular: пароля

So:

• без пароля = without a password

This is a very common pattern in Russian:

• без сахара = without sugar
• без машины = without a car
• без времени = without time

Here нельзя means something like you can’t, it’s impossible, or it’s not possible.

So the structure is:

• нельзя + infinitive
• нельзя войти = it’s impossible / not allowed to enter, log in

In this sentence, the meaning is mainly practical impossibility: if you do not have a password, logging in cannot be done.

Because не можно is not normal modern Russian.

Russian uses the pair:

• можно = one may / it is possible
• нельзя = one must not / it is impossible

So:

• Можно войти = It is possible / allowed to log in
• Нельзя войти = It is impossible / not allowed to log in

For an English speaker, нельзя is best learned as a single word, not as не + можно.

It can mean either, depending on context.

In this sentence, it most naturally means cannot:

• Без пароля нельзя войти в аккаунт.
• Without a password, you can’t log in to the account.

But in other contexts, нельзя can mean must not or not allowed:

• Здесь нельзя курить. = You must not smoke here.

So the word itself covers both impossibility and prohibition. Context tells you which one is meant.

Because войти is perfective, and here Russian is talking about the completed result: successfully getting into the account.

• войти = to enter / log in successfully
• входить = to be entering / to enter regularly or in general

In login-related sentences, войти is very common because the focus is on the completed action:

• Не могу войти в аккаунт. = I can’t log in to the account.

If you used входить, it would sound more like a repeated, habitual, or process-based idea, which is not the main point here.

Because after в, Russian uses different cases depending on meaning:

• в + accusative = motion into
• в + prepositional = location in

Here, войти means to enter, so there is movement into something:

• в аккаунт = into the account

Compare:

• войти в аккаунт = to log in to the account
• быть в аккаунте = to be in the account

So аккаунт is in the accusative case, but for this noun the accusative looks the same as the dictionary form.

Because this is an impersonal construction, which is very common in Russian.

Russian often says things like:

• Можно войти. = It is possible to log in.
• Нельзя войти. = It is impossible / not allowed to log in.

There is no stated subject, but the meaning is general:

• you
• one
• people
• anyone

English usually needs some subject or a different structure, but Russian often does not.

Yes. Аккаунт is a very common modern Russian word, especially in tech, apps, websites, and social media.

It is a borrowing from English account. In everyday digital Russian, it sounds normal.

There is also a more formal or official Russian equivalent:

• учётная запись = account

So you may see both:

• войти в аккаунт
• войти в учётную запись

The first is more common in everyday speech and many online contexts.

Yes.

You could say:

• Без пароля нельзя войти в учётную запись.

That is correct Russian. It sounds a bit more formal, technical, or official.

By contrast:

• аккаунт sounds more modern, conversational, and common in everyday internet language.

So both are possible, but аккаунт is very natural here.

Yes, absolutely. That version is very natural too.

Both are correct:

• Без пароля нельзя войти в аккаунт.
• Нельзя войти в аккаунт без пароля.

The difference is mainly emphasis.

• Без пароля at the beginning emphasizes the condition: without a password
• Putting it at the end is a bit more neutral

Russian word order is flexible, and speakers move elements around to highlight what matters most.

Sometimes yes, especially in casual speech.

• войти в аккаунт = the most standard and neutral way to say log in to an account
• зайти в аккаунт = more conversational, a bit like go into / hop into an account

In app interfaces, help pages, or more standard wording, войти в аккаунт is usually the safer choice.

Because Russian has no articles like a or the.

So аккаунт can mean:

• an account
• the account

The exact meaning depends on context.

In this sentence, English naturally says the account or sometimes just your account, but Russian does not need a separate word for that. The context supplies it.