Blank first ad; Proper second/third ad

What do you think?

[acac]

I am seeing something funny.
My first Ad block shows nothing (read white space). However my second and third blocks shows ads. I tried changing channels etc. without effect. It is determined to make the first ad block for one site always blank.

Does it make any sense at all? What could be causing it?
Help appreciated.

[Porkchop]

Wait a while to see if the ads show up. Sometimes a new page takes longer before all ads will show.

[jimbeetle]

Another possibility: Google fills the ad blocks in the order they appear in the html. If there aren't enough ads to fill all of the blocks the ones lower down will be blank.

You might want to check to be sure that the first ad block you see on the page is actually the first ad block in the code.

[acac]

The site is pretty old. The first ad is not showing for any pages - old or new. And always the second and third ads are showing. And no I am not making any mistake.
I am 100% positive that it is the first ad block which is going empty.

And it has never happened before.

If anyone is interested I can post the url in sticky notes.

What baffles me is that by all common sense the second and third ad units may be missing, but the first!

Also I use both image & text ads, so no issue on that front either.

Update: Solved the problem. My mistake. Some code from an old Adlink code was left behind which apparently caused this.

Thanks for all your help.

[sallam]

being the first ad viewable in your page doesnt necessarily mean that its the first in your page's html code.
For example, if you're using tables, it could be up on top right column, while there are 2 in mid and bottom left rows.
The one on top right side, then, actually shows up third in your html code.

[remove]

i've had problems like this which i attributed to google's slownes. usually after 2-3 reloads the ad will show up just fine. it seems like if you had time to change the channel, this is a problem which has occurred for a longer period of time though? did this specific ad ever work?

[acac]

1. The problem has been solved.

2. It was the first ad (in html) which was showing this issue.

3. It happened because I had some old code fragment from AdSense AdLink code left behind. After I removed that everything was back to normal.

Thanks for all your suggestions.