Little more than year ago there was same problem.
It was like this.
cwop.aprs.net is not one server. It can be redirected to one of 7 servers.
Not all servers has the same software.
Problem was in password.
It was "-1 ver WiFiLogger"
should be "-1 vers WiFiLogger"
It can be also -1, but 3/7 servers were rejecting "-1 ver" - so there was no upload, but sometimes it was good.
CWOP as I know, but it is not have to be truth. They would like to have 5 min. interval.
Please use
http://YOURS_WFL_IP/debug to check answer from CWOP servers. It will help to solve your problem.