My main house internet ( older copper cable telephone line from German Telekom) kept failing a few weeks ago. A nice lady from German Telekom on the phone tried to troubleshoot the problem for me, and finally used her charm to get me to give up trying to fix the problem and take out a new contract for a slightly better / faster internet connection with them instead.
I have got that system up and running, after a fashion , but it still has a few problems, including this one which is the subject of this Thread.
In case it might be relevant , this is what I had:
DSL 16.000 RAM IP ( The router was a 10 year old German Telekom Speedport W504V Typ A )
Download: Max. 16 MBit/s, Normal 9,5 MBit/s, Min. 6,304 MBit/s
Upload: Max. 2,4 MBit/s, Normal 1,5 MBit/s, Min. 0,704 MBit/s
And this is my new system
VDSL 50 ( The new router is a FRITZ!Box 7590 )
Download: Max. 50 MBit/s, Normal 47 MBit/s, Min. 27,9 MBit/s
Upload: Max. 10 MBit/s, Normal 9,4 MBit/s, Min. 2,7 MBit/s
The problem:
Some of my XP machines, stubbornly refuse to accept the WLAN password for the new FRITZ!Box 7590 Router, and chuck up this strange error

That error message is
Das Netzwerkkennwort muss zwischen 40 Bit oder 104Bit, abhängig von der Netzwerkkonfiguration, sein.
Das Kennwort kann in der Form von 5 oder 13 ASCII-Zeichen oder 10 oder 26 Hexadezimalzeichen eingegeben werden.
The translation is approximately
The network password must be between 40 bits or 104 bits, depending on the network configuration.
The password can be entered in the form of 5 or 13 ASCII characters, or 10 or 26 hexadecimal characters.
The WLAN password number I am trying to give it is
29719228817028334572
That number works on some XP machines and all my Vista, Win7 and Win 10 machines.
( My old router is still turned on and connects successfully with all my XP machines ( it cannot give me internet because it does not work with the faster VDSL ), and it's password is accepted by all my XP machines. The number is
3716565511074969 )
( German Telekom are no use, I have had a few technical questions at their various help forums on them over the years and always ended up answering them myself. They think I am an expert, so they must be idiots! )
I expect I will sit down and look at this problem in detail next week, so I thought I would ask in advance if anyone here has any ideas for me to think about in the meantime, and/ or try out.
If all else fails I suppose I will compare all settings and software on the XP machines that have and don’t have this problem and see if I can track down the problem in that way. There is some info to be found in internet talking about WPA encryption things and similar which I don’t have a clue about, but I expect I might have to learn :(
Thanks
Alan