The default limit on items returned when creating an External List is 2,000. When trying to return more items, you get the following non-descript error:
Unable to display this Web Part. To troubleshoot the problem, open this Webpage in a Microsoft SharePoint Foundation-compatible HTML editor such asMicrosoft SharePoint Designer. If the problem persists, contact your Webserver administrator.
When you hit this issue, you have two options: apply a filter as described earlier in this chapter or increase the limit. To change this limit, you need to get someone with Farm Administrator and Local Administrator rights on one of your SharePoint Web front-end servers to run the following PowerShell commands;
$bcs = Get-SPServiceApplicationProxy ...