I wasted lots of time, cleared my browser cache, etc.
I was trying to add a new wire service payee. I did some cut-and-paste into several fields, and each time the creation process ended with a "technical issue," no further detail.
I kind of blundered into the issue. The cut and paste include the "&" character, and this input was accepted. However, when I did direct typing into the same fields and tried to type in an "&" character, the website did not accept the input. When I replaced the & with the word "and" as needed, I was able to create that new payee.
This behavior in the website accepted by a supervisor in the phone/online support department as a bug in the website.