Some mobile carriers have specific words blocked to prevent spam messages from being sent to their customers. If a blacklisted word is used anywhere in the message body, the SMS will fail.
Mobile carriers do not provide a list of blacklisted words and phrases, and there is no way to whitelist them, but the list below includes words and phrases that have been known to cause an SMS message to fail:
Credit
Loan
Bit.ly
Anything alcohol-related, including alcohol brand names such as Miller, Coors, Budweiser, Patrón, .etc
Cryptocurrency (for some countries such as the United Arab Emirates)
Anything gambling-related
Anything drug-related, including marijuana
ATT
Firearms brand names or references to weapons
Financial aid