XML error: not well-formed (invalid token) at line 1

Hi,
I use financial business (my site: lamdongreal.vn) and sometime I see this error when visiting the site from the frond-end (not ever happened when login from the back-end):

XML error: not well-formed (invalid token) at line 1

Some searchs on the internet tell me that this error caused by the template.
Please have a look on my site and help me to fix this. Remember, the error just appears sometimes, maybe right at the first page you visit or after you've browsed a few pages. If it happen to be no problem, please leave the site for a few minutes and come back later.
Here is a screen shot of the error:

Thanks

Just seen it twice, few refreshes and it is gone.

As it is not displaying at all times then it could be caused by plugins / components / languages / server speed etc so it would be difficult to pinpoint.

If you haven't made any changes and it was working fine before then it could be your server resource issue.

Otherwise look for any additions you have done and go backwards steps , such as if you installed any modules or plugins disable or uninstall them.

Are you using any feeds such as RSS from other websites by the way?

See you around...

I didn't make any changes for a few months. I just update every news (k2).
There are 3 modules display RSS feed from other sites at the bottom. Does it cause the problem?
I don't know why I don't receive any notification via email about new post on my topic?

Try disabling those modules for test purposes.

As error is related to XML and only occurs sometimes then its highly remote site generated xml in RSS feeds.

See you around...

Thanks Norman. I'll try and let you know.

Also recently there has been problems with Google servers, I am not sure if its related to their IGoogle Api which they are thinking of stopping.

So if you have any modules using above servers it might be caused by above.

See you around...