I followed the lead from johntankard and just reinstalled v1.1.7 on top of the three units with v1.2.0 that were giving problems. No need to revert to factory settings or re-apply the backed up configuration.

All now back to normal. Thank you John for posting your experience.

Interesting I have another site also running v.1.2.0 and this is working without any problems....

Cheers, Dave

mtcsltd wrote: thank you admin. Your advice worked. I reset to factory default, downgraded to 1.1.7, then restored my config files. It's all working fine now, no problems with mobile device clients any more.

If you have the opportunity, please contact support and pass them an example config file they can check to see if they're able to reproduce the issue.

Thanks admin, I sent them the config file two weeks ago.

As the later f/w has critical updates, I'd still report this to DrayTek and ask for it to be looked into and not stick with the old f/w.

After battling with my 2 AP902s for most of the weekend, I have also downgraded the firmware to 1.1.7.3 - fingers crossed I no longer have issues, otherwise I'll be reverting to 1.1.5.2!

It's so difficult to troubleshoot these devices, there is a complete lack of decent logging that I can see - is there more comprehensive logging hidden away in the telnet or something?

In the spirit of unhelful answers... yes, probably Perhaps Telnet or syslog provides some info. I have an AP900 but I've never had to troubleshoot it.