@TReimann Strange. You have unzipped the file? Is router and controller on same network?

@TReimann Yep, no problem here. are you using a controller or stand alone

@Freddo You find the latest firmware for ER605v2 in this url. https://www.tp-link.com/en/support/download/er605/v2/#Firmware where do you use subnet mask 255.255.255.248 is this between ASA and...

@Freddo I don't know, there is probably something wrong with the ASA configuration, have you tried the cisco forum :-) I did a trace here but I don't have an ER605 in front.. I have this software...

Have you configured dns on your ASA ? Try ping somthing with name from console on your ASA or configure ASA dns with this command dns domain-lookup outside DNS server-group DefaultDNS name-server...

@Dixon_Herize Try and update your firmware on the router and controller if you use that.