Excel to SharePoint 365 Connection Causes Security Error

RMcCreavy
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Excel to SharePoint 365 Connection Causes Security Error

Post by RMcCreavy »

Hello,

I've been seeing errors consistently when attempting to connect to SharePoint 365 via Excel. The message box is titled Microsoft Excel Security Warning
and reads: "Certificate Error. The application experienced an internal error loading the SSL libraries."
Excel_Security_Warning.png
This occurs both when I try to refresh data in an excel table that is connected to a SP 365 list (originally exported from SharePoint as an .iqy file) or when I try to save a file directly to a SP 365 doc library with VBA.

This issue only popped up after the recent Log4j debacle, but it's unclear so far if it is the result of a change on Microsoft's end or something patched internally. However, the TLS and internet security settings on our Windows servers (in addition to everything Office related) appear unchanged so everyone I have discussed this with internally is stumped.

Has anyone here experienced a similar issue in the past?
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HansV
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Status: Microsoft MVP
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Re: Excel to SharePoint 365 Connection Causes Security Error

Post by HansV »

Which TLS version do you use?
Best wishes,
Hans

RMcCreavy
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Posts: 39
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Re: Excel to SharePoint 365 Connection Causes Security Error

Post by RMcCreavy »

1.2

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HansV
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Re: Excel to SharePoint 365 Connection Causes Security Error

Post by HansV »

Update to enable TLS 1.1 and TLS 1.2 as default secure protocols in WinHTTP in Windows mentions some of the registry settings required for TLS 1.2.
Best wishes,
Hans

RMcCreavy
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Posts: 39
Joined: 02 Nov 2018, 16:12

Re: Excel to SharePoint 365 Connection Causes Security Error

Post by RMcCreavy »

TLS.png
Based on that support page, I have TLS 1.1 and 1.2's DisabledbyDefault value set to 0, but unfortunately the error persists.
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HansV
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Re: Excel to SharePoint 365 Connection Causes Security Error

Post by HansV »

I'm not a SharePoint expert. I hope that someone else can help you!
Best wishes,
Hans

RMcCreavy
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Posts: 39
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Re: Excel to SharePoint 365 Connection Causes Security Error

Post by RMcCreavy »

Thanks Hans!