what is a simulator

[Leon50 Aeon]

its saying unable to connect to simulator

[Freya Mokusei]

Simulator definition

SL Forum: Unable to Connect to Simulator error

This happens every Tuesday (and some Wednesdays), it's when some simulators go offline for updates. I'm kind of impressed that you've never seen it happen before.

And the weekly Grid Status confirms this:- 

 

[uPDATED] Rolling Maintenance RC Server Channels

[updated 07:00 AM PST, 09 December 2015] The rolling maintenance for the RC server channels is in progress.

[Posted 7:45 PM PST, 08 December 2015] We will be performing rolling maintenance for regions on Magnum, BlueSteel and LeTigre RC server channels beginning at approximately 7:00 AM PST tomorrow, December 9th. Please refrain from rezzing no-copy objects and making in world L$ transactions, and remember to save all builds. For more information about the specific RC server channels, please refer to the links below.

[Rolig Loon]

A simulator is a server that runs all of the programs that appear to create reality in a portion of Second Life that we call a region, sometimes loosely called a "sim".

In your case, the problem is that it's Wednesday morning, and your region is probably one of those undergoing routine maintenance.

[uPDATED] Rolling Maintenance RC Server Channels

[updated 07:00 AM PST, 09 December 2015] The rolling maintenance for the RC server channels is in progress.

[Posted 7:45 PM PST, 08 December 2015] We will be performing rolling maintenance for regions on Magnum, BlueSteel and LeTigre RC server channels beginning at approximately 7:00 AM PST tomorrow, December 9th. Please refrain from rezzing no-copy objects and making in world L$ transactions, and remember to save all builds. For more information about the specific RC server channels, please refer to the links below.

http://wiki.secondlife.com/wiki/Beta/BlueSteel
http://wiki.secondlife.com/wiki/Beta/LeTigre
http://wiki.secondlife.com/wiki/Beta/Magnum

I suggest either logging in to a different region or waiting until meaintenance is completed.  You can always check on the Grid Status blog whenever you have a question about maintenance issues.

[Madelaine McMasters]

Hi Leon,

Simulators are software, running on computer servers in the Linden Lab server farms. Each simulator manages one region, and there are multiple simulators (and therefore regions) running on each server. All that you see when you enter a region is served up by the simulator. It's responsible for communicating avatar positions and states to the viewers of everyone on the region, as well as detecting and managing collisions between objects, running scripts, routing chat traffic and a bunch of other things.

When you see the message you described, it means that the simulator running the region you are trying to enter is either down, or there's a communications issue preventing your viewer from connecting to it. If it's the former, you'll just have to wait until the server/simulator restarts and is again accepting avatars. if you're seeing this message across many places you're trying to go, it's likely you have an iffy connection to the SL servers. Here's a web page with ideas for improving that connection...

http://blog.nalates.net/2011/10/26/troubleshoot-your-sl-connection/

Good luck!

ETA: Oh yeah, as Rolig and Freya have mentioned it's always a good idea to check the grid status first when you see that message.