Imap not downloading emails after certain date

I am working on Email client application.

I have written one sample program for downloading emails from Gmail account using IMAP client library, It downloads emails from AllMail folder.

Here I am facing very different problem. my sample application won’t download emails after certain date.

Actually I have created my Gmail account in Jan 2009 and my sample program downloads emails up to Sept 2009 only, not downloading email sent/received before Sept 2009, even though more emails exists between Jan开发者_如何学C 2009 and Sept 2009 in my Gmail AllMail folder.

I have tried same account with Thunderbird Email to check this issue, Strangely Thunderbird also has got same issue (downloading emails up to Sept 2009 only).

Can you some one help what is wrong with my Gmail account setting?

Note: I have configured my Gmail account with IMAP only.

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This may not actually be a date limitation but a mailbox size limitation. Double-check that your GMail IMAP settings for Folder Size Limits is set to "Do not limit...".

Also, above the IMAP settings, check the POP settings to see what date it has set for its limit (if any). I don't know if the two are tied together or not, but if the POP limit is September 2009, that would be suspicious.