File type, size, or server limits can block an upload.
When an attachment is refused, check type and size before assuming a bug.
Quick checks
- Use PNG, JPG, PDF, TXT, LOG, or ZIP when those types are allowed.
- Stay under the size limit shown beside the upload control.
- Executable and script files are always refused.
- Large logs belong in a ZIP.
Server limits
PHP upload_max_filesize and post_max_size must be large enough. If the browser upload fails, ask hosting to raise them or send a link to the file in your reply.