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This product reached the end of support date on March 31, 2021.

When collector or server is restarted Windows server agents have an error "Instrumentation is not available"


Hi folks,
I have this repetitive problem, when we restart or we off the collector server (for maintenance, etc) the windows server agents have this problem. The solution? restart the Iis, but why this is a problem? because the IIS is an production application we can't restart the server in every time...
This is a bug? I have the version 6.5.16


DynaMight Leader
DynaMight Leader

Hello Alexander,

In this situation you must have a collectors group because if a Collector fails due to hardware or software failure, the Agents buffer data from a couple of seconds to up to a minute, depending on load. As a result, no data is lost if the Collector is started again within this time.

You should use more than one Collector for Agents of the same type (Agent Group / tier) and configure Collector groups in a production environment.
If the Collector comes up within a minute again, the Agents will automatically reconnect to the Collector and the latter to the Server.
If not, the Agents can fail over to a different Collector in the Collector group.

Please also check the following link for all the components HA installations.



Dynatrace Champion
Dynatrace Champion

hi Alexander,

the message "Instrumentation is not available" means that an Agent (in your case I guess an IIS with a .NET Agent) is started up and cannot connect to a Collector in time, which in turn completely disables the instrumentation. this is an architectural requirement, because the instrumentation is done by the Collector and has to happen at application startup.

in your scenario I guess that IIS worker processes are (automatically?) restarted in the time frame when the Collector is down (Server does not matter).

there's 2 approaches to this issue:

  1. as Babar already mentioned: use Collector Groups. this will work as long as you're not bringing all Collectors from the group offline at the very same time. as long as one Collector in the group is available, the Agents will be able to restart correctly and instrumented.
  2. in the future we will switch to a new Agent architecture (the OneAgent), which will be capable of instrumenting autonomously, thus getting rid of this startup-Collector-dependence. however, it will take us some more time to get this ready as it's currently (for .NET) still in BETA status (

HTH, Christian