ArgumentException using HTTPHeader on more than 28 rows

When using a formula like =HttpHeader("http://"&A2&"/","Server"), where A2 is a domain name, when trying to apply this to a large list (thousands) of domains, a large percentage of the responses are ArgumentExceptions. If I drag the formula down 28 rows, none return an ArgumentException, when I drag it down 29, one of the rows will return ArgumentException. (though it isn't the last row)

Using Excel 2013 32bit and seotools 7.0.8.

Hi Evan,

Can you provide a sample of the domain list so I can try to reproduce the errors?

Well after my system rebooted (win10 updates) and I reloaded the spreadsheet and did testing again, I can't replicate the problem.

Having said that, I still have issues on some sites. For instance: www.lehman.aecglobal.com I couldn't get it to see the Server Header until I disabled Cache and/or enabled debug mode. Now it sees it on http:// but even with debug mode is failing on https:// (dodgy cert but debug should ignore that)

and nevermind on the https, looks like it redirects to a site that times out...but http:// should have worked without changing settings. I'll try to find a better example.