SMTP error what should I do?

Greetings! The SMTP error you are experiencing, often referred to as smtp error.7.1 https://www.massmailsoftware.com/smtp/554-5-7-1/, is usually a response from the recipient's mail server indicating that your email could not be delivered. There are several factors and circumstances that can cause this error. The most common reasons include sending to an invalid or non-existent email address, having your email marked as spam, or exceeding the recipient's email size limit. To successfully send a message, start by double-checking the recipient's email address for accuracy. Make sure your email content does not contain spam-like elements such as excessive links, certain keywords, or attachments that may trigger spam filters. Also, avoid sending large attachments that may exceed the recipient's email size limit. Maintaining a good sender reputation is critical, so adhere to email best practices.