One of Murphy's laws (or was it a corollary to it) stated: If you have loosened n-1 screws of n, you find that you open the wrong unit.
In a radio-RRC there are three passwords and two usernames
(1) IP-settings: WEB-page user, WEB-page pwd;
(2) Dynamic DNS settings: User name, Password
(3) Radio Settings SIP-Password
Guess what I actually used and what I should have used. Most users seem to set them all alike, violating their administrators' recommendation, but avoiding my problems.
Many thanks Jan and those discussing off reflector for putting me in the right direction!
73 Gerd
DJ4KW V31YN