I have Mikrotik RB750r2 that bought 1 month ago.
Now, got Error - "Simultaneous Session Limit Reached" and also error "RADIUS accounting request not sent"
any one can help me, please.
I attach the screenshot.
thankyou.

There's some kind of problem with your radius server when receiving accounting, that's what first error points to (are you using radius?).

Second message, logging failing due to simultaneous session limit reached could mean (if you're using radius), your radius server or service is not being notified of users disconnecting (as radius is not reachable) and thinks these users are still active.

Yes, I am using Radius.
so, what's the solution of its error?

To fix whatever is happening to the radius server, if you're using SQL backend the problem is usually there. How many users?

Alternatively, to alleviate the problem, if radius is being "overloaded", you can try to ease the load on it, by:

- setting the Hotspot server profile interim update to 10 or 15 minutes
- increasing Radius timeout to 3s (3000)

Could you post a screenshot of radius Status tab?

This issue should be resolved in 6.40 version if you use User Manager:
*) userman - do not send disconnect request for user when "simultaneous session limit reached";

To fix whatever is happening to the radius server, if you're using SQL backend the problem is usually there. How many users?

Alternatively, to alleviate the problem, if radius is being "overloaded", you can try to ease the load on it, by:

- setting the Hotspot server profile interim update to 10 or 15 minutes
- increasing Radius timeout to 3s (3000)

Could you post a screenshot of radius Status tab?

My WiFi network is less than 20 user.

here is my RADIUS Status

This issue should be resolved in 6.40 version if you use User Manager:
*) userman - do not send disconnect request for user when "simultaneous session limit reached";

I use ROS 6.35.4
and I use RB750r2
so, Can I update the ROS to 6.40 ?
I mean, is 6.40 version is good for my RB750r2?

To fix whatever is happening to the radius server, if you're using SQL backend the problem is usually there. How many users?

Alternatively, to alleviate the problem, if radius is being "overloaded", you can try to ease the load on it, by:

- setting the Hotspot server profile interim update to 10 or 15 minutes
- increasing Radius timeout to 3s (3000)

Could you post a screenshot of radius Status tab?

I use idle timeout = 5 minutes.
so, must I try change it to 15 minutes?

To fix whatever is happening to the radius server, if you're using SQL backend the problem is usually there. How many users?

Alternatively, to alleviate the problem, if radius is being "overloaded", you can try to ease the load on it, by:

- setting the Hotspot server profile interim update to 10 or 15 minutes
- increasing Radius timeout to 3s (3000)

Could you post a screenshot of radius Status tab?

and I use RADIUS timeout 300
must I try it change to 3000 ?

What was the router uptime when you posted that status screenshot? Doesn't look like unresponsive radius on that screenshot; I thought it was actually an external radius server, not user-manager running on the same router.

Yes, you should upgrade to current 6.40.1, check System > Routerboard afterwards that Current Firmware matches Upgrade Firmware.

- Set timeout to 1000
- look again at status after 24hours

What was the router uptime when you posted that status screenshot? Doesn't look like unresponsive radius on that screenshot; I thought it was actually an external radius server, not user-manager running on the same router.

Yes, you should upgrade to current 6.40.1, check System > Routerboard afterwards that Current Firmware matches Upgrade Firmware.

- Set timeout to 1000
- look again at status after 24hours

actually, the condition now was OK. and I post screenshot above when my router was ok.
I am still not found any error again till now, after make a change for set timeout of radius to 3000 and idle time hotspot profile to 15 minutes.

but, I will still look forward for some next day. If I got error, I will report again here.

by the way, if I upgrade my ROS from 6.35.4 to 6.40, Whether it will change my router settings or not?

here is SS for my router ROS version.

Dear mikrotik expert person I have RB1100AHX4 dude edation ARM

I getting this error

simultaneous session limit reached

Pleaee see the attach file