Errors when providing supporting documentation

The most common errors arising when submitting complementary documentation are as follows:

• Error 400:this error usually appears in computers with slow data transmission speeds or when files are too large.In these cases, we recommend sending documentation in several small deliveries or fragmenting the file.
• File not accepted (formatting error, location, etc).It is recommendable that the file to be attached does not have a very long filename, or forbidden characters (commas, periods, apostrophes, cedillas, &, quotation marks, etc.)or that it be larger than the permitted size when sending the corresponding documents.It is also recommended that the file be located in the path C:/AEAT If this path does not exist on your computer, you can create it to locate the file, as it is sometimes essential.
• I can't see the window for selecting the file:this is usually due to a browser setting or because you are accessing the procedure from an incorrect link.We recommend that, if you are using Windows, you contribute via Mozilla Firefox, Edge or Google Chrome, as Internet Explorer 8 or lower is not supported.