Log Name: Enterprise Vault
Source: Enterprise Vault
Event ID: 41352
Task Category: Index Volumes Processor
Level: Error
Description:
The processing of the Index Volume has stopped following errors.
Archive name: Archive Name
Task:
Index Volume ID: 1E13E909A5BDD9649B68C75462C443D3F1110000server_103
Reason:
Error Type: NonCritical
Description: Indexing engine unreachable. Inner exception: The remote server returned an unexpected response: (413) Request Entity Too Large.
v-437-41352
The IIS logs show:
2022-07-08 22:43:37 ::1 POST /EVIndexing/Velocity.exe v.app=api-soap& 443 - ::1 - - 413 0 0 15
The IIS SSL setting for client certificates is set incorrectly. It is set to Accept for the /EVIndexing virtual directory. It should be set to Ignore instead.
Note: There are two variations of this issue. They can be distinguished by the IIS log substatus code shown in the above log snippet immediately after the 413 http status code. This solution is for when it is zero (0), as in 413.0.
If the IIS logs show 413.2 instead, that issue has been addressed in EV version 12.5.1 and later versions. See related article.
Solution
Change the setting for client certificates to Ignore for the /EVIndexing virtual directory in IIS manager.

Fig. 1: SSL settings (in IIS section)

Fig. 2: Client certificate setting
Indexing doesn't work. Index Volumes Processor logs event 41352 as shown below. This can affect all index volumes on the EV server.