Inputs window with Loading message

After I have set under Inputs Send EMail I only have a white input window with Loading message

Feeds are displayed normally.

A reboot did not change.
I can not change the input parameters any more
Emoncms Version low-write 9.8.0 | 2017.02.01 ,Local installation
This error came only after the update to 9.8.0

After I cleared the Redis cache, the Inputs page is displayed correctly.
$ redis-cli flushall.