As of version 220.127.116.11 of Aspose.Network.dll, the attached text file causes the method Aspose.Network.Mail.MailMessage.Load() to fail if read from either a stream or a file. The problem seems to be that an interal buffer in the lexer or parser used during the load is set to 1000 characters, so if you have more than 998 characters on a line before a \r\n, the Load() method never returns. This bug is simple to reproduce once you know what it is. The attached eml file contains a paragraph containing a single line with 999 characters followed by a \r\n. You can reproduce the problem by trying to load the message using the Aspose.Network.Mail.MailMessage.Load() method. If you delete the X at the end of the line it will load, otherwise, it will hang. Hopefully it should be simple to fix. 998 characters plus a \r\n is the max. This problem occurs in the real world, because I’ve had my process totally hang because it tried to load an html email with no newlines that exceeded this limit. Since HTML does not require newlines, this is not uncommon.
Thanks for posting the sample file and providing a detailed analysis too. I have reproduced the bug at my end and also added it in our bug tracking system (ID: 16843). We will notify you when it will be resolved. Sorry for the inconvenience.