A web page has a mailto: links. When a user clicks a link that has over 5 or 6 email addresses e.g. HTTP code (<a href="mailto: email address, email address, email address etc…) Notes does not create a new message with email addresses in the To: field.
Subject: RE: Lotus Notes mailto: link from the browser
If it works when there are fewer email addresses (but more than one), that suggests you’re running into a length limitation of the URL. How many characters long are the individual email addresses? Do they contain special characters that must be URL-encoded (which uses up more characters)? Is there any way to abbreviate them? Are you sure that each of the email addresses in the list that fails, works when it’s used alone in a mailto link? Maybe one of them has an odd character that causes a URL syntax error.
If some recipients are members of the same organization, you might consider making a group of them in your mail server, so that the email could be addressed to the group instead of to a list of individuals.