Wifi signal received but no connection

Both of my access points give a signal, both are WPA secured.
With my laptop I have connection and data stream.

With my Galaxy S, the indicator gives a signal on both of the access points, but no data stream.
Sometimes it works when I enter my house of switch the phone on.

But most of the time there is a good signal without data stream. Apps tell me that there is no connection.

What goes wrong?

So if i`m reading your post correctly... you have been able to connect to your WiFi on occasion!

It could be that the phone is turning WiFi off when screen goes off..
try this:

Go to...

-menu
-settings
-Wireless & Networks
-Wi-Fi settings

Then hit the phones "Menu" button while in the Wi-Fi settings screen..

You will see two options pop-up: Scan or Advanced

Click on Advanced then select "Wi-Fi sleep policy" and choose "Never"!

Hope this helps!

-----
Download AndroidPIT's AppCenter! AndroidPIT FAQ – Frequently Asked Questions and Answers

Malfidus, do you never have an internet connection when using your Wi-Fi network on your Galaxy S device, or do you only sometimes have problems connecting to the internet?

-----
Recommended reading for new AndroidPIT members! Important to all community members: the AndroidPIT Forum rules

Nope, it didn't help, the option 'Never' was on already.
But thanks for you explanation, I didn't knew about this possibility.

I have sometimes an internet connection....
My Galaxy S device shows the sign that there is an connection, but using the internet it says "no connection".

Added info:
It worked with several other open wifi networks and secured.
It doesn't work either with only one access point on in my house.

Are you sure that MAC filtering isn't enabled on that router?

-----
Download AndroidPIT's AppCenter! AndroidPIT FAQ – Frequently Asked Questions and Answers

I thought about that as well, but would he even be able to connect at all if that was the case?

Malfidus, are you actually ever connected to the router, or do you only see that the network is available when you go inside your wireless network settings?

-----
Recommended reading for new AndroidPIT members! Important to all community members: the AndroidPIT Forum rules

The Mac addresses in the routers are off.

I had a connection on my network, but after a safety configuration the troubles have started.

Yesterday I was in a open network area, I had immediately a good contact.

This brought me to the idea to disable the security mode in the routers and guess what...
It all worked fine.
But I don't want to leave my wifi network open. And it doesn't work either with a low WEP configuration.

Do you have an idea if there is something to configure on the Samsung Galaxy S I9000 that it can work well in a secured network?
I use an Wireless G access point and a Wireless G router, both from Linksys.

Back when I had a Galaxy S, it was able to work with our secured network as long as MAC-address filtering was disabled. Have you tried playing around with different encryption forms to see if one works?

-----
Recommended reading for new AndroidPIT members! Important to all community members: the AndroidPIT Forum rules

I presume, I have to switch this off on the access points?

Yeah, it has to be done on the router.

-----
Recommended reading for new AndroidPIT members! Important to all community members: the AndroidPIT Forum rules

HI!
Same problem with my Motoluxe. The telephone sits on the kitchen counter for a few hours and sometime when I want to use it: guess what? No access to WiFi. When I go to menu/network & Wireless, it tells me that I'm connected to my network, with excellent signal (about 3 feet from router), but the icon at the top of the screen says No WiFi. Had this problem about 3 time in the last month, never had before that. Every time I have to factory reset the phone and loose every userdefined data I put in it. It's a PITA to reload the phone every week. Between the time the WiFi works and the time it doesn't, no change to router, phone, software. Doess that for ne apparent reason...

Any idea? Is it the harware, Android, the operator or the whales in the Atlantic?