Hi @Hoamboy! 

You can find down below the settings of the router. No connection, the dongle is blinking continuously green and red in a loop.
(I am trying to use username and password as well in the picture)

I also send the correct types of the devices in case of any misunderstanding.
Router: https://www.tp-link.com/hu/business-networking/omada-sdn-router/er605/
USB Doungle: https://www.amazon.com/HUAWEI-E3372-Broadband-Unlocked-Network/dp/B013UURTL4

Thank you,

  @szabadi 

Okay, so *99# seems to be the right dial-up number for cellular modems in general.

Don't know where you have *36# from.

In case you're referencing to international country code 0036 for Hungary then this is wrong as it has nothing to with it.

Let's stick with *99# and this should be fine.

Obviously you don't need username/password for Telekom Hungary - this is where you are correct, so leave these fields empty then.

APN internet.telekom seems also correct.

Can you play with Authentication and IP settings.

Set Authentication to 'none' or 'auto' and IP to 'IPv4/IPv6' and see what happens.

MTU 1480 for mobile connections is also fine - no change here.

PS: And 'Link up' will only be shown when you're successfully connected - and only then.
So with settings above, please click the 'Connect' button and see what happens.

Hi  @Hoamboy!

Thank you for your answer.
I agree, the dial number must be *99# as well. I investigated my misunderstanding about that dial number.

I tried every variations of the Authentication Type, unfortunately nothing changed.

I don't understand what can be the problem because on my pc, I added the same fixed parameters to the usb dongle and it works every time (in the USB Dongle GUI there is no dial number, that is the only difference).

Thank you,

  @szabadi 

I have the same issue and I'm not able to establish connection. It looks that the E3372 modem has several subtypes and not all are supported by ER605. I think that TP-Link should update compatibility list with more details.  

  @szabadi 

For me ALCATEL IK41VE1 works OK with ORANGE POLAND SIM card.

For info, I stopped using my IK41VE1, as it was getting a lot of drop-outs, so I went and bought a Huawei E3372h-320 and everything ran smoothly. 

If you have an external 4G LTE aerial with TS-9 connectors, then it might be worth a try with the Huawei Brovi E3372-325 to see if it was just it's poor gain, that was giving you issues. You could always use the came aerial on the E3372h-320, if it didn't work out.