Hi @nitishrana, 

Welcome to the Klaviyo Community! We are so glad to have you here, thanks for sharing your question! 

SMS carriers take Spam risks and messages very seriously in order to protect their users from unwanted messages. Not only do they have a sensitive radar to quickly mark something as spam if it seems questionable, but it is also illegal to message users without their consent and you can be fined. While Klaviyo does not have a spam detection resource to scam your message before you roll it out, we do have some general guidelines and best practices you can follow to help ensure you’re SMS compliant and your messages will reach your users’ phones:

• Get Express Consent to Send Customer SMS Messages
• Give Recipients a Way to Opt Out
• Explain What Someone is Opting Into
• Comply with Time of Day Restrictions

Not abiding by one of these principles outlined above might have caused your SMS campaign to fail. I suggest checking out these SMS Compliance Laws and SMS Sending Best Practices to have a better understanding of what kind of content is appropriate for SMS. 

While these guidelines are helpful when evaluating your SMS sending, we recommend that you consult an attorney to ensure that your text messaging program and policies comply with US SMS laws and carrier guidelines. 

Thanks for being a part of the Community, 

Taylor