Wifi Access Point instable in Fedora, KDE Plasma 5

Question

I have two PCs (PC1 and PC2). Both have identical hard- and software and both are connected to the interenet via ethernet connection. As OS I have Fedora 23 with KDE Plasma 5. Using the KDE Connection-editor, I have created on both PCs an Wifi Access Point (AP1 and AP2 using "Wireless shared"). Most things I kept as default. I've only set the SSID, freq=2.4GHz, the channel and a password with WPA&WPA2 Personal. After that, the files /etc/sysconfig/network-scripts/ifcfg-AP1 and ...../ifcfg-AP2 were created on the PCs. There, I only added IPADDR0=<ipaddress> to assign an static IP address to my APs.

The problem: After several hours it is not possible anymore for a client to connect to the APs. Only a restart of the PCs enables the APs again. After a reboot, clients can use the APs again but the wifi download rates are very (~600kb/s) slow but the uplode rate is much higher. After a few hours, the connection gets lost again.

I've tried to find some hints in the log files: When a client connects to an AP, the following appears in /var/log/messages:

Apr 28 09:50:08 MyName dnsmasq-dhcp[2506]: DHCPDISCOVER(wlp5s0) <HWADDRESS>
Apr 28 09:50:08 MyName dnsmasq-dhcp[2506]: DHCPOFFER(wlp5s0) <IP OF CLIENT> <HWADDRESS>
Apr 28 09:50:08 MyName dnsmasq-dhcp[2506]: DHCPREQUEST(wlp5s0) <IP OF CLIENT> <HWADDRESS>
Apr 28 09:50:08 MyName dnsmasq-dhcp[2506]: Ignoring domain <MyDomain> for DHCP host name <HOST>
Apr 28 09:50:08 MyName dnsmasq-dhcp[2506]: DHCPACK(wlp5s0) <IP OF CLIENT> <HWADDRESS> <HOST>
Apr 28 09:50:11 MyName dnsmasq-dhcp[2506]: DHCPINFORM(wlp5s0) <IP OF CLIENT> <HWADDRESS>
Apr 28 09:50:11 MyName dnsmasq-dhcp[2506]: DHCPACK(wlp5s0) <IP OF CLIENT> <HWADDRESS> <HOST>

Then every minute thhis message is logged:

Apr 28 09:51:31 MyName dnsmasq-dhcp[2506]: DHCPINFORM(wlp5s0) <IP OF CLIENT> <HWADDRESS>
Apr 28 09:51:31 MyName dnsmasq-dhcp[2506]: DHCPACK(wlp5s0) <IP OF CLIENT> <HWADDRESS> <HOST>

After several hours, when the APs are broken again and I try to connect to the wifi with a client the connection fails and thses messages do not appear in the log files anymore.

You probably need further informations about my system. I will provide them if you tell me what you need and how can I get them because I'm not an advanced Linux user.