WifFi connection / ssid / 2.4GHz vs. 5GHz

Hi all

Reaching my limit with what I could find in this forum and on the internet, maybe you have a clue where to look further. Also, I am no geek but a newbie and just learn to use cmd lines and the whole environment.

I know LAN is preferred, but for the IBD I decided to access the 2nd network due to the higher speed (2Mbps vs. 20Mbps) but I have no access to a LAN port (and I might learn something trying to activate WiFi). I’m using a Pi 4B.

I use the wpa_supplicant.conf guidelines to connect to the 1st (2Mbps) WiFi(1) and it works like a charm. The same procedure however doesn’t work on the 2nd (20Mbps) WiFi(2).

One difference I can spot is the SSID of WiFi(2) has a " " (space) in it (ssid=“word1 word2”) I read this could cause an issue but doesn’t have to. I also experimented with different variations (ssid=word1 word2, ssid=word1\ word2) without success.

Another difference I can see is WiFi(1) (which I can connect to) has a 5GHz band, whereas WiFi(2) (which I can’t connect to) has a 2.4GHz band. Can’t imagine this to be an issue, just saying what I observe with limited capabilities. Note: a connection to WiFi(2) from my laptop works without problem, just my Pi can’t connect.

Where do I need to look further?
What did I not consider?
How do I troubleshoot this?

Thanks for your input