There are a number of reasons why you may see the "This message was blocked because its content presents a potential security issue" error in Gmail. Gmail blocks messages that may spread viruses, like messages that include executable files or certain links.
Why messages get blocked
To prevent against potential viruses, Gmail doesn't allow you to attach certain types of files, including:
- Certain file types (listed below), including their compressed form (like .gz or .bz2 files) or when found within archives (like .zip or .tgz files)
- Documents with malicious macros
- Archives whose listed file content is password protected
- Archives whose content includes a password protected archive
Note: If you try to attach a document that is too large, your message won't send. Learn more about attachments and file size limits.
File types you can't include as attachments
.ADE, .ADP, .BAT, .CHM, .CMD, .COM, .CPL, .EXE, .HTA, .INS, .ISP, .JAR, .JS (NEW)
, .JSE, .LIB, .LNK, .MDE, .MSC, .MSI, .MSP, .MST, .NSH .PIF, .SCR, .SCT, .SHB, .SYS, .VB, .VBE, .VBS, .VXD, .WSC, .WSF, .WSH