Error Message

The following (or similar) may be seen instead of the expected Enterprise Vault options:

And when you try to access OfficeMailApp.aspx you may see below:

When attempting to load the Enterprise Vault Office Mail App in OWA 2013 or later, a call is made to load JavaScript and CSS files (as per the OfficeMailApp.aspx page response) from the Enterprise Vault Server.  Under certain circumstances, the file access may respond with 403 18 (Unathorized) causing the Office Mail App to display unexpected results.

1) Replicate the issue while running the IE Network Capture / Fiddler and review the log.  Multiple entries referencing the Enterprise Vault Virtual Directory may be returning a “403” result.
2) Try to browse the corresponding file from IIS going to the content view and confirm if it can be opened or not.

3) If these files give 403.18 IIS error code page, then try to review the "Physical Path" in the error page which may show: C:\inetpub\wwwroot\Rejected-By-UrlScan

IIS logs may also show:

GET /Rejected-By-UrlScan ~/EnterpriseVault/V12.2.0.1437/OfficeMailApp/Redist/css/Style.css 443 - 10.180.130.224 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+10.0;+WOW64;+Trident/7.0;+.NET4.0C;+.NET4.0E;+.NET+CLR+2.0.50727;+.NET+CLR+3.0.30729;+.NET+CLR+3.5.30729;+wbx+1.0.0) https://XXXXXXXXX/EnterpriseVault/officemailapp.aspx 403 18 0 2
GET /Rejected-By-UrlScan ~/EnterpriseVault/V12.2.0.1437/OfficeMailApp/OfficeMailApp.css 443 - 10.180.130.224 Mozilla/4.0+(compatible;+MSIE+7.0;+Windows+NT+10.0;+WOW64;+Trident/7.0;+.NET4.0C;+.NET4.0E;+.NET+CLR+2.0.50727;+.NET+CLR+3.0.30729;+.NET+CLR+3.5.30729;+wbx+1.0.0) https://XXXXXXXXX/EnterpriseVault/officemailapp.aspx 403 18 0 5

4) If it is showing the above 'URLScan', then check the default configuration file folder of the same: \system32\inetsrv\urlscan\
5) The above location would contain logs folder, open the recent log and find if you see any lines such as:

2018-06-20 08:40:29 172.30.12.81 1 GET /EnterpriseVault/V12.2.0.1437/OfficeMailApp/redist/css/Style.css Rejected URL+contains+dot+in+path URL - -
2018-06-20 08:41:52 ::1 1 GET /EnterpriseVault/V12.2.0.1437/OfficeMailApp/redist/css/Style.css Rejected URL+contains+dot+in+path URL - -

6) If yes, suggest the customer allow the traffic since URLScan is something which is restricting OfficeMailApp to load fine.
7) Once resolved you should be able to open the default OfficeMailApp.aspx page to show the gray bar.