problem PPPOE SERVER - peer is not responding

Salve,
da qualche giorno senza cambiare nessuna configurazione ho 1problema sulla mia rete..questi i log del pppoe server:

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

ho controllato la tratta in trasparent bridge e sembra tutto ok.il collegamento รจ a -54db con 1ccq del 98%. nei log di tutti gli apparati non risulta nessun errore.si disconnette solo il pppoe-client la wlan dei client rimane sempre registrata..a rotazione del tutto casuale si disconnettono tutti o quasi tutti i client.il tutto si ripete ogni 5/10min circa.. ho letto di questo problema sia su questo forum sia su altri ma non ho trovato nessuna soluzione..qualcuno sa aiutarmi??
ho allegato lo schema della mia rete

I checked the route in trasparent bridge and it all looks ok. the connection is a-54db with 1ccq of 98%. in the logs of all the equipment is not no errore.si pppoe-client disconnects only the wlan client is always recorded in rotation .. totally random disconnect all or almost all client.il everything is repeated 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

grazie anticipatamente

tanks