PROBLEM PPPOE SERVER - peer is not responding

Hello,
a few days without changing any configuration I have a problem on my network .. these logs pppoe server:

18:43:47 pppoe,ppp,info <pppoe-0>: disconnected 
18:43:47 pppoe,ppp,info <pppoe-0>: waiting for call... 
18:43:49 pppoe,info PPPoE connection established from 00:5C:XX:XX:XX:XX 
18:43:49 pppoe,info PPPoE connection from 00:5C:XX:XX:XX:XX was already active - c
losing previous one 
18:43:49 pppoe,ppp,info <pppoe-0>: terminating... - disconnected 
18:43:49 pppoe,ppp,info <pppoe-0>: disconnected 
18:43:49 pppoe,ppp,info <pppoe-0>: waiting for call... 
18:43:55 pppoe,ppp,info <pppoe-0>: terminating... 
18:43:55 pppoe,ppp,info <pppoe-0>: disconnected 
18:45:48 pppoe,info PPPoE connection established from 00:5C:XX:XX:XX:XX 
18:45:48 pppoe,ppp,info <pppoe-0>: waiting for call... 
18:45:49 pppoe,ppp,info <pppoe-0>: authenticated 
18:45:50 pppoe,ppp,info <pppoe-0>: connected 
18:45:50 pppoe,ppp,info,account UTENTE logged in, 10.0.0.197 
18:45:50 pppoe,ppp,info <pppoe-UTENTE>: using encoding - MPPE128 stateless 
18:46:54 pppoe,ppp,info,account UTENTE logged out, 65 98 94 8 7 
18:46:54 pppoe,ppp,info <pppoe-UTENTE>: terminating... - peer is not respondi
ng 
18:46:54 pppoe,ppp,info <pppoe-UTENTE>: disconnected 
18:47:51 pppoe,info PPPoE connection established from 00:5C:XX:XX:XX:XX
18:47:51 pppoe,ppp,info <pppoe-0>: waiting for call... 
18:47:51 pppoe,ppp,info <pppoe-0>: authenticated 
18:47:51 pppoe,ppp,info <pppoe-0>: connected 
18:47:51 pppoe,ppp,info,account UTENTE logged in, 10.0.0.197 
18:47:51 pppoe,ppp,info <pppoe-UTENTE>: using encoding - MPPE128 stateless 
18:51:33 system,info,account user admin logged out from XX:XX:XX:XX via winbox 
19:03:28 system,info,account user admin logged in from XX:XX:XX:XX via winbox 
19:09:26 pppoe,ppp,info,account saro.spadola logged out, 3935 6221554 112666864 62
618 87036 
19:09:26 pppoe,ppp,info <pppoe-UTENTE>: terminating... - peer is not respond
ing

I checked the route in trasparent bridge and it all looks ok.il link is a-54db with CCQ 98%. in the logs of all devices do not contain any error. disconnects only the pppoe-client wlan client is always recorded. rolling completely random disconnect all or almost all of the clients. then it repeats approximately every 5/10min .. I read about this problem both on this forum and on others, but I found no solution .. someone can help me?
I have attached the schematic of my network

thanks in advance

Can you post your configuration settings?