This issue is related to TLS RC4 security ciphers still in use on Constant Contact servers. If you grab one of the images from your newsletter and drop it in Internet Explorer you will receive the following notice: This page can’t be displayed Turn on TLS 1.0, TLS 1.1, and TLS 1.2 in Advanced settings and try connecting to https://files.constantcontact.com again. If this error persists, it is possible that this site uses an unsupported protocol or cipher suite such as RC4 (link for the details), which is not considered secure. Please contact your site administrator. This link explains the cipher a bit more: https://support.microsoft.com/en-us/topic/rc4-cipher-is-no-longer-supported-in-internet-explorer-11-or-microsoft-edge-f8687bc1-1f88-9abe-5c81-b00c26290f36 Unfortunately, turning on TLS 1.0, 1.1, and 1.2 doesn't make a difference. Constant Contact needs to work on using modern security ciphers to resolve this issue permanently for everyone.
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