Serviio block / ban only one client

i use:
- Serviio 1.5.2 on Windows 8.1 64 Bit with 8GB RAM
- iPad mini 2 with 16GB, PlayerXtreme (Pro Version)

I stream on a iPad videos. Thats works fine. But when i want to look later again, the player app dont find serviio. the only solution seems that i delete the ipad ip in the serviio renderer profile list. then it works fine for the moment. a reboot of the ipad, serviio pc and router without delete the ipad from the profile list seems not to work . My Samsung TV works always fine without this problems....
what can i do that serviio dont block / ban the ipad?

[DenyAll]

Does the IP address of either the server or the iPad change? Does the player cache the server address - is there a way to delete the server from the list/cache?