Check four things: did you send the file itself or a link they can’t access, is it under their email’s size limit, does it need a password you didn’t share, and is it a dynamic form only Adobe Reader can show? Send yourself a copy first — if it opens for you from your inbox, the problem is on their side.
Runs in this tab, on pdf-lib, qpdf (WebAssembly) and pdf.js, so your file is read from your own device and never sent anywhere. Check it yourself
How do I fix it?
1Email it to yourselfOpen the copy from your own inbox, ideally on a phone. If it fails there too, the file is the problem; if it opens, ask what they see.
2Check the sizeUnder 10 MB is safe for almost any workplace mailbox. Compress it to fit, or split it into parts, before sending again.
3Send the password separatelyIf you protected it, share the password by another route, and tell them to expect it.
4Repair or re-exportDrop it on Repair PDF and press Repair PDF: it confirms the file really is a PDF and rewrites it cleanly. Send that copy.
5Replace dynamic formsIf it shows “Please wait…”, export a standard PDF from the form software, or print it to PDF from Adobe Reader once filled in.
Why does this happen?
It needs a password they don’t have. If you protected the PDF, they need the password too. Send it separately — by text or a call, not in the same email.
It was too large, and stripped. Many workplace mail systems reject or strip attachments over 10 or 20 MB. The email arrives, the PDF doesn’t, or arrives as a broken file.
You sent a link they can’t open. Cloud links (Drive, OneDrive, Dropbox) open only for people they are shared with, and some expire. To the recipient it looks like the PDF won’t open.
It was damaged on the way. Rarely, an attachment is altered by a mail gateway or a forwarding chain. The file they receive is no longer the file you sent.
It is a dynamic XFA form. Forms built with Adobe LiveCycle open only in desktop Adobe Reader. In browsers and phone apps the recipient sees “Please wait…” and nothing else.
It isn’t really a PDF. A Pages, Word or HTML file renamed to .pdf opens on your machine because your system knows what it is; theirs doesn’t.
Questions
Why can I open my PDF but others can’t?
Your computer has the original, a password you remember, or the right app. Test by emailing it to yourself and opening it from there, on another device.
What size PDF can I safely email?
Under 10 MB gets through nearly every workplace system. Gmail allows 25 MB; Outlook 20 MB from the app. Compress or split anything larger.
Should I send a PDF as a link or an attachment?
An attachment is easier for the recipient. Use a link only for large files, and check its sharing settings before sending.
What does “Please wait… If this message is not eventually replaced” mean?
The PDF is a dynamic XFA form that only desktop Adobe Reader can display. Open it there, or ask for a standard PDF version.