It has become a cliché that spam messages can often be spotted through errors in the body text. There might be simple typos, or grammatical mistakes, sometimes because it is obvious that the language used in the email is not the sender’s native language.
It is extremely uncommon, virtually unheard of, for mega-corporations like Microsoft or Google to email users and suggest visiting another link because of a security problem. They have billions of customers, after all. If there is a typo or grammar error in an email purportedly from a company like this, it should be a double red flag. Yes, big companies can make mistakes too, but how likely is it that they will compose an email to millions of people, and nobody catches a simple error?
Hackers are getting wise to this signal, naturally, so the quality of spam emails is improving. This means even more vigilance is necessary.