We are having the exact same issue discribed This is the exact issue we having as well https://vox.veritas.com/t5/Enterprise-Vault/EVS-from-Outlook-add-in-reporting-quot-your-search-reque...
Hope someone can assist
Currently having a very strange issue, At random when user clicks on Enterprise Vault Search with in outlook get an error "Your Search request failed. Wait and try again. If the problem presists, contact your Enterprise Vault Administrator" But at the same time if I use the Web browser it works fine. Even if I restart the services the Outlook Client error does not resolve. But after about 30 mins it starts working.
Exchange 2010 SP3, MBX on DAG
Outlook 2016 x86 EV Version 22.214.171.1245
EV server is on Windows 2012R2, 2X servers one purely for Indexing
Have checked EV logs during the issues but not able to find any errors. Logged support calls but they are unable to identify and have tried chaning IIS settings which has not helped.
Have tried DTrace with support but they are not able to pin point any errors
When tried on Fiddler logs get a resonse 400,
This is the exact issue we having as well https://vox.veritas.com/t5/Enterprise-Vault/EVS-from-Outlook-add-in-reporting-quot-your-search-reque...
Since you've spoken with Tech Support, some of our questions could be redundant.
When you say that the issue is not seen in the web browser, are you trying to access the same user's archive on the same computer? (may be a naive question).
Have you tried to change this setting in the policy and see if there's any difference?
Guess, sometimes workarounds are simply not enough.
When you changed the policy, you say you haven't observed the issue. What's the frequency of the issue? Every week, every two weeks? Have you kept the policy for that time frame to confirm that there hasn't been a single problem in that timeframe? have you tried using an older but supported version of Outlook?
In any case, I understand from the post that all the users seem to complain about this issue. Since it is intermittent, there's a threshold being reached which causes it to break. When it breaks for one user, do other users simultaneously complain or is it just that user in that time frame?
You may want to check this post again and see if the solution works for you as well.