Break stream or disconnecting when use RouterOS & Freeradius

Hi Friends,

I use RouterOS as PPPOE server and Freeraidus as radius server for my users.
I meet a thorny difficult problem as below:

When I use above solution in FTTP users(about 200 users), all is ok. When I use the solution in ADSL users(about 150 users), many users report break stream frequently(15-25%). In such cases, I stop Freeradius server and use RouterOS to authentication, the issue will be decreased greatly.

Base on some information in internet, I guess this issue may occur if RouterOS don’t coordinate with Freeradius very well.
So I set some options, for example, set “Use Encryption” to “no” in PPPOE profile of RouterOS. But I still can’t solve this problem.

Can you help or give me some advises?

Thank you very much!

Robin Lu