What app are you using?
++Adding to the discussion,
I am reading other suport discussions, and I have to ask if you are using the web browser in your phone to access a PDF linked to a website?
Where are you trying to download this PDF from (if that is the case)?
Is your Adobe Reader mobile app configured as the default PDF handler in your mobile device? And have you configured your web browser to download PDFs files instead of opening directly in the browser? Is this happening from a cloud storage service such as Dropbox or GoogleDrive, for example?
Check if in your browser (Chrome based or Mozilla) that you don't have thhe "Automatic Downloads" preference blocked.
Do the same and check in the "Downloads" preference setting and ensure that you have configured a download location folder in your device. Then toggle on "Ask where to save files".
None of this is probably related just yet to your issue until you confirm if this is related to how you have configured your device with your web browser and your Adobe Readder mobile app first.
If that is the case, compare the settings of your Galaxy 8 with the current settings of your Galaxy 10.
If for some reason you suspect the problem is on the Playstore side of the Google house, use this link as alternate download : https://get.adobe.com/reader/otherversions/
NOTE: This download is only 21 MB if you're doing it over cellular data (which I don't think is the issue) try also doing the download from the Playstore over a fast Wi-Fi connection instead of using your data plan.
I also forgot to mention to check in your Galaxy 10 what is the default storage location: Internal Memory or an external SD Card. Make sure that if you're installing the APK file to an brand new SD Card that it is formatted and accepted by the mobile device.
The Gmail app won't let you view PDFs natively with the Adobe Reader mobile app nor in a web browser.
Most of these new services only provide support for their own PDF viewer. It seems like this may be the issue. This is true with Dropbox, Whatsapp, and maybe with the Micrososft Sotre.
In your Firefox browser, go to settings--->>General-->>"Custom Tabs" toggle off that option that says "Allo apps to open web content in a quickly loading custom tab".
And also set you Adobe Reader app as the default PDF handler =in your mobile device.
I am looking into other things but is taking me longer than expected. Theere are some built-in settings and defaults in the mobile version that are different from the desktop version.
Would you get the same error with another web browser? like Chrome or the new Micrososft Edge browser (which is Crome based)
With the same settings that I suggested I am able to do a long press on a weblink that contains a PDF and select if I want it to open in the web browser or with Acrobat Reader.
See slide below:
Tapping on Always make the Reader Mobile app my default PDF viewer.
But I'm afraid that if this is problem that you're having is happening with Gmail, you may not be able to do this.
Your only option left is to try and Save As PDF which will download directly to your device using this method.
Also check if the link is down. Try with other links. If my suggestion in the slide works with other links you'll have to seek support from Google and see what is the issue there.
try with a link outside of gmail.
try this link as an example:
If it works with this link but not with Gmail the issue is with Google. They block users from having this type of PDF workflow.
If the problem happens with the link above or any link outside Gmail you may need to perform an manual update of Firefox or uninstall it and reinstall again.
do you get the 404 error while using cellular data or over a Wi-Fi network?
Can you browse other pages with firefox?
Do you get the same error when you click on any other link on a Google search?
Can you confirm if the browser is working properly?
We need to rule out that the browser is not working.
404 messages appear when a server is up but the requested page that you're trying to hit is not available.
Please confirm if you're able to at least browse the Internet with both WiFi or cellular.
So what you're saying is that you were able to access PDFs directly in Google using the Gmail app or Mozilla Firefox browser?
Please update the thread.
I said earlier that companies like Google, Dropbox or Microsoft block users from opening PDFs directly in the Adobe Reader mobile app.
I also mentioned that they block in some browsers this workflow and that it forces the PDF document to open in their own supported PDF viewers, not even giving a chance for the browser to download the file.
I would appreciate if you can confirm this so I don't continue to suggest erroneous guidance to users with a similar problem.
Update has stopped me downloading pdf on ringo Park app.says I need a pdf viewer. Used to work just fine in Adobe.