Php imap_search() FROM criteria using email address doesn't work in outlook

I know this isn't Laravel related exactly but I am building a project with Laravel, and one of my classes is a wrapper for an imap interaction using php imap. Since this is a such an excellent forum, well, here it goes.

I'm building a class that connects to an IMAP server. In my development environment I tried connecting to Gmail successfully, getting emails like this:

$emails = imap($this->connection, "FROM \"$source->email\" ");

The line above works as expected, it returns an array with the emails that matched the criteria, it works perfectly. e.g if $source->email = myemail@example.com, it will return only emails from that address.

However, when testing with the client's account in outlook I get an empty array using the same criteria. Even if the email address is static id doesn't work:

$emails = imap_search($this->connection, 'FROM "myemail@example.com"');

But doing the following does not return an empty array:

$emails = imap_search($this->connection, 'ALL');

The goal of the class is to extract some data from the emails, these emails are grouped by email addresses. Each group displays the content in a different pattern, so I have to distinguish all of them in order to instantiate the proper class that can extract the data from that group.

Any ideas on how to debug this ? or what might be the problem ?

Thanks.