Amazon SES : Getting transient bounce ContentRejected on notification mails, Cannot modify content

I have been using aws ses to send notifications to my customers since long. However, recently all the notification mails are getting bounced with reason as ContentRejected. The mail simply notifies user when a user shows interest in his services which is my platform's main business. I cannot play much with the content since its already very concise and even when I tried to rephrase it, its getting bounced. I send these mails only to users who have subscribed to receive these alerts. This has started happening today only and I have no way finding out if someone might have marked these mails as spam ( may be mistakenly) since all my mails have an option to unsubscribe. Please help as my business largely depends on these notifications. Following is the subject and content that I send:

Subject: New Lead for {company name}: User {user mobile} has shown interest in your business Mail Body: Congrats ! User with mobile no {user mobile} seems to be interested in your products/services. The user just visited your link {clicked link} on {Click date} from IP address {IP Address} .' The user seems to belong to {IP Location}, Zipcode: {IP Zipcode} . * Location is approximate. <p> The lead has come through the message {message content} sent by you on {sent date}*