In case this helps anyone - keep your WiFi access point passwords relatively short to avoid issues with AP management on router 2862.

I use KeePass to generate passwords for stuff so I used it to create a 20 character password for "admin" on a new AP902 WiFi access point. I found two problems:

2. the "AP/Status" page on my Vigor2862 router (despite updating the "Account" settings) could not access the AP


4. copying WLAN profile to the AP failed.

When I reset the "admin" password on the AP902 to 9 characters and updated the "Account" settings on the "AP/Status" page, everything worked as expected.

I haven't had time to experiment to see what the maximum length of password is, the manuals I've seen certainly don't mention this limit, and maybe I've just misunderstood something...

...but I hope this helps you!