Nope. Did not work unfortunately. This does not make any sense to me. Could there be some kind of dhcp conflict with the router?

No I don't think it is a captive portal w authentication. I am not sure what u mean but there is no need to do any kind of login to go online once u have a normal connection to the AP much like a home WiFi. So I guess the settings on the AP are pretty basic. I only know that the AP which is onthe beach sometimes bogs down at peak times because it can only handle up to 100 clients. But I have tried to do everything off peak when I get a good connection on my tablet or phone. As I said before the pinging diagnostic is my test for a good connection.

Yes i tried your suggestion before about inputting 11bg mixed instead of 11bgn mixed. This lowers the mhz and bandwidth automatically to 54mbps and 20 mhz but as i said it did not work.

OK I tried range ext 2 and also lowering the channel spacing 20mhz and trying lowering the Mbps to eg 54 or 130. I do not know the Mbps of the router but it is a recent model zte 931vii vdsl2 according to the AP gateway login which I can see but d not have thepassw to. So I guess the Mbps should be quite high. I will try now changing the ssid although as I said before the RE has worked quite well with three other AP's I tried but they were not public AP's although I fail to see what difference that would make with this setup. And the firmware is the latest version. Is it worth reflashing?

The last two days I cannot connect to the AP with the RE. I can connect with my tablet normally but the RE runs through its setup but is disconnected from the AP according to the menu. Reconnecting or rebooting or resetting does not help.

Ok but my RE is the 830.....

Try pulling the battery, an error may occur and the device must be restarted