Hello,

Try to add the following code snippet to the Custom CSS area in Theme Settings to fix this issue.

.woocommerce-message, 
.wpcf7-mail-sent-ok {
    color: #dd3333;
    border-color: black;
}

.woocommerce-error, .woocommerce-info, .woocommerce-message, div.wpcf7-response-output {
	border-width: 1px;
  	border-style: solid;
  	font-size: 16px;
}

Regards