vCenter Discovery: Unable to establish connection

[danielherre]

Hi community, a question about VMware Discovery.

We have 3 ServiceNow instances (DEV, PRE, PRO) which need to discover the same 2 VMware vCenters.
Each of the instances has an independent MID server, for all of them we have checked and confirmed network traffic is allowed in the firewall on TCP ports 443, 5480 y 9443.
VMware credential de VMware is the unique, has been configured on the three instances and Test Credential is successful for both vCenters, on th three instances.

From the DEV instance, we can successfully discover VMware CIs using a configuration items type discovery schedule.
But in PRE and PRO instances, using similar configuration and specifying the correct MID server, we are getting error message:
15/12/2025 17:23:25 Warning Unable to establish connection to https://<vCENTER_IP_ADDRESS>/sdk

From PRE MID Server, accessing https://<vCENTER_IP_ADDRESS>/mob from a browser is successful and the user pass grants us access.

Setting the MID server on debug log level, we only see one difference.
On the failing instance:
2025-12-12 14:53:06+0100 DEBUG (Worker-Standard:VMWareProbe-bdef6b011bf5b2501b92a9b1604bcb27) [MIDScriptIncludes:144] MID Script Include cache miss for name=VMWarevCenterDatacentersProbe
Whereas on a successful discpovery on the DEV instance we see:
2025-12-12 16:35:44+0100 DEBUG (Worker-Standard:VMWareProbe-4567c8d587b93e107356113e3fbb359b) [MIDScriptIncludes:104] MID Script Include cache hit for name=VMWarevCenterDatacentersProbe

Thanks!!

[mahamst31]

Hi @danielherre, 

I searched your query and found this helpful article that contains the following resolution steps:

1. Check the production instance, which is usually the source for clones, and so will not have been affected.
2. Find the MID Server Script Include mentioned in the error.  In the above examples, that is "Class":
   https://<instance_name>.service-now.com/ecc_agent_script_include.do?sys_id=bb6e3cd3c0a8020100823824cbacec99 
3. Export that file as XML, and import it into the instance that is missing it.
4. To avoid breaking instances after future clones, please remove any custom setting specific to MID Servers that include code.

Try this, maybe this can resolve your issue.

Whole article link is here:

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0818891

If you find my response helpful, mark it as helpful and accepted solution.

Regards, 

Maham Tahir.

[danielherre]

Hi Maham,

thanks for the reply, here it does not fully apply because we have just deployed new MID servers for the three instances, no cloning process has taken place.

Regards,

[SP22]

Hello @danielherre,

vCenter Discovery messages

Message: Unable to establish connection to https://10.249.17.207/sdk

• No VMWare type credential is stored in the credential table.
• The username is a domain account and needs to be prefixed with a domain.

Thanks
Santosh.P

[danielherre]

Hi Santosh,

well here credential has been stored con the three instances, in DOMAIN\username format and successfully validated. Even on the failing instance we have tested with username@DOMAIN format, but same failure message. I wonder if it is really trying the connection to the vCenter., we see some traffic in the firewall to the vCenter, but the vCenter admin colleague does not find our login attempt in their logs.