Tofaktorautentiseringen stopper forsøket på innlogging.

Because Norwegian very often makes compound nouns by writing them as one word.

So:

• to = two
• faktor = factor
• autentisering = authentication

Together, they form tofaktorautentisering = two-factor authentication.

Then the ending -en is added to make it definite:

• tofaktorautentisering = two-factor authentication
• tofaktorautentiseringen = the two-factor authentication

This kind of long compound is completely normal in Norwegian.

The ending -en is the definite article attached to the noun.

In English, you usually put the before the noun:

• the authentication

In Norwegian, the definiteness is often added to the end:

• autentisering = authentication
• autentiseringen = the authentication

So tofaktorautentiseringen means the two-factor authentication.

In Norwegian, a noun often becomes definite by taking an ending, instead of using a separate article like English the.

So:

• English: the login attempt
• Norwegian: innloggingsforsøket or forsøket på innlogging

In this sentence:

• Tofaktorautentiseringen already means the two-factor authentication
• forsøket already means the attempt

That is why you do not need a separate the before them.

Stopper is the present tense of å stoppe = to stop.

So:

• å stoppe = to stop
• stopper = stops / is stopping

In Norwegian, the present tense is often used where English could say either:

• stops
• is stopping

So Tofaktorautentiseringen stopper forsøket på innlogging means:

• The two-factor authentication stops the login attempt
• or, depending on context, is stopping the login attempt

Because forsøket is the definite form of forsøk.

• et forsøk = an attempt
• forsøket = the attempt

The sentence is talking about a specific attempt, not just any attempt in general.

So:

• stopper et forsøk på innlogging = stops an attempt to log in
• stopper forsøket på innlogging = stops the attempt to log in

Here på is part of the expression forsøk på ..., which means attempt at ... or attempt to ....

So:

• et forsøk på flukt = an attempt to escape
• et forsøk på innlogging = an attempt to log in / a login attempt

This is not always something you can translate word-for-word. It is just a normal Norwegian pattern:

• forsøk på + noun

Innlogging is a noun meaning logging in or login.

It comes from the verb å logge inn = to log in.

Compare:

• å logge inn = to log in
• innlogging = logging in / login

So:

• forsøket på innlogging = the attempt to log in / the login attempt

English often uses login very freely as a noun. Norwegian can also do that, but the form innlogging is a very standard native-style noun.

Yes, very often you could.

Both are understandable:

• forsøket på innlogging = the attempt to log in
• innloggingsforsøket = the login attempt

The compound innloggingsforsøket may sound a bit more compact and technical, while forsøket på innlogging is slightly more expanded.

In many contexts, both are natural. Norwegian often allows both a compound noun and a noun phrase with a preposition.

Yes. It follows the standard Norwegian main-clause pattern:

• Subject: Tofaktorautentiseringen
• Verb: stopper
• Object: forsøket på innlogging

So the structure is:

Subject + verb + object

This is very similar to basic English word order:

The two-factor authentication stops the login attempt.

The given sentence is understandable and grammatically fine, especially in technical or formal language. But in real Norwegian, people might often prefer slightly different wording depending on context.

Possible alternatives:

• Tofaktorautentisering stopper innloggingsforsøket.
• Tofaktorautentisering hindrer innloggingen.
• Tofaktorautentisering stopper forsøket på å logge inn.

A few notes:

• hindrer = prevents
• forsøket på å logge inn = the attempt to log in

The original sentence is not wrong, but Norwegian technical writing often has several equally possible ways to express this idea.

A useful way is to split it into parts:

to-faktor-autentisering-en

You do not need to say it as one giant mystery word. Norwegian speakers mentally hear the parts inside the compound.

A learner-friendly breakdown:

• to
• faktor
• autentisering
• -en

If long compounds feel difficult, that is normal. A good strategy is:

1. Find the last part first: autentiseringen
2. Then work backward: faktorautentiseringen
3. Then the full word: tofaktorautentiseringen

That is often the easiest way to decode long Norwegian nouns.