AnkiDesktop is working well and syncs to AnkiHub. However, on Ankimobile, I can see the text on the card but cannot see any images. When trying to sync it says my cards differ in such a way that I need to download from Ankiweb. However, when I do that, it will not sync completely. I can see all of the correct cards there, but they will not show any images. The error says “HttpError { code: 303, context: “reading stream”, source: Some(Custom { kind: ConnectionAborted, error: “stream failure (code=303)” }) }”.
The main issue is that on Ankimobile I cannot see any images on any cards. It says “an image is missing paste-.jpg”
How to troubleshoot this issue?
Please look at these forum topics where other people saw the same error message: Httperror code 303
and Get HTTPError() code:303 when I try to sync
Do you live in a geographic region where internet connections are known to be blocked or otherwise not reliable? Or, are you using a firewall or VPN which might affect your internet connectivity?
Also, you mentioned that your Anki desktop app syncs correctly with “AnkiHub”. However, you did not say whether it syncs correctly with AnkiWeb. Does it?
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The Anki desktop app syncs correctly with Ankiweb as well. I am not using a firewall or VPN and my internet connection is stable and reliable. Neither of the forum topics linked helped. Now when I try to sync, I get the error message “A network error has occurred. Error details: error sending request for url ()” However, my internet connection is stable and reliable and my Anki desktop syncs on the same network. Also, when I tried on another network, it still failed.
The only problem I have is that I cannot see images on Ankimobile. I can see all of my cards on Ankimobile, I just cannot see the images on the cards. Also, now on my Anki desktop, it says “Anki was unable to open your collection file. If problems persist after restarting your computer, please use the Open Backup button in the profile manager” (I got the same message after restarting and when I tried to open backup, it did not allow it)… all of my cards are there and usable, so I am not sure if/what I need to do about this.
I redownloaded Ankimobile and signed in with my account to synchronize. It said “local collection has no cards. Download from Ankiweb?” I hit ok, and it downloaded all of my cards correctly. However, it then again said “A network error has occurred. Error details: error sending request for url ()” … so it said it was unable to sync and again I cannot see images on Ankimobile, it says the images are missing.
I don’t know what is going on 
As I understand it, you are experiencing 2 separate problems:
- On the Anki desktop app: You are seeing the error message: “Anki was unable to open your collection file. If problems persist after restarting your computer, please use the Open Backup button in the profile manager”. The message persists when you restart your computer, and when you try to Open Backup, the operation fails.
- What OS version are you using?
- What Anki version are you using?
- In the desktop Anki app, have you tried Tools → Check Database to see if that might fix the issue?
- When did this issue start? Was there a time when you were able to use the Anki desktop app without seeing this problem?
You say that the Anki desktop app is able to sync and upload to AnkiWeb just fine. However, until Problem #1 is resolved, I am not sure if I fully trust that syncing is working correctly.
- On the AnkiMobile app: When trying to sync to download, you see the error message: “A network error has occurred. Error details: error sending request for url ()”. This error was seen when using two different network connections on your device. And, it seems that media files were not downloaded to your device. You are not using a firewall or VPN.
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I will be more direct: Do you live in Russia or China? If the answer is “yes” then you may need to try using a VPN to resolve this issue.
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You previously said that you saw a different error on AnkiMobile: “HttpError { code: 303, context: “reading stream”, source: Some(Custom { kind: ConnectionAborted, error: “stream failure (code=303)” }) }”. However, you now say that you are no longer seeing this error. Is this correct?
Edit: Added:
- You may also want to reboot your router to see if that might help. (Though, since you said the problem occurred using two different network connections, it seems that doing this might not help.)
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I have a Windows 10 Pro, Version 22H2, OS build 19045.6456 and I have Anki version 25.07.5 (7172b2d2).
I just re-opened Anki desktop and it worked without saying the error message “Anki was unable to open your collection file. If problems persist after restarting your computer, please use the Open Backup button in the profile manager”. That issue started today but has now resolved, I guess? However, now it will say Anki cannot open because it is already running (which it isn’t) and the only way I can open the app is to restart the computer.
I tried the tools –> check database.
Yes, it appears that Anki desktop app and Ankiweb are in perfect sync.
Yes, if I go to https:ankiuser.net/study and review I can see the images correctly on cards
I do not live in Russia or China.
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You previously said that you saw a different error on AnkiMobile: “HttpError { code: 303, context: “reading stream”, source: Some(Custom { kind: ConnectionAborted, error: “stream failure (code=303)” }) }”. However, you now say that you are no longer seeing this error. Is this correct? This is correct
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On the AnkiMobile app: When trying to sync to download, you see the error message: “A network error has occurred. Error details: error sending request for url ()”. This error was seen when using two different network connections on your device. And, it seems that media files were not downloaded to your device. You are not using a firewall or VPN. All of this is also correct
There’s a lot going on here. Thanks for trying to help.
Okay, let’s focus on the AnkiMobile issue.
On your device:
- What OS version are you using?
- What version of AnkiMobile app are you using? (gear icon (to go to the Preferences page) → About)
- When did this problem start? Have you ever been able to download images when using the AnkiMobile app on this device?
- You said you tried 2 different network connections. Were they: Your residential home internet via wifi, and Cellular data? If not, which network connections were they? Were either of them your work or school wifi?
Some troubleshooting ideas:
- Try fully powering off and on the device, to see if that might possibly help.
- Try other different network connections. For example:
- Turn off wifi to try having AnkiMobile use cellular data.
- Turn off cellular data to force wifi usage, and then try a few different wifi connections. For example public wifi at local stores, restaurants, or libraries.
- If you have a VPN available to you, try using a VPN connection
- (The working theory is that it is the network connection that is the problem. But, if the issue were to occur with a number of different network connections, then it would suggest that the problem is elsewhere.)
Also, it takes time for media files to download. Even when things are working correctly, sometimes users need to leave the AnkiMobile app running in the foreground and/or repeat the sync process multiple times before all the media files fully download.
- Perhaps try leaving the AnkiMobile app running in the foreground for a while during the sync to see if any media files actually get downloaded? (A long shot, but just in case the error message might be some sort of false message that can be ignored.)
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On my iPad I am using OS version 18.7.2 and on Ankimobile I am using 25.09? I am not sure because when I go to gear icon (preferences) –> about … it just says, “thank you for buying AnkiMobile!” and then has 25.09 at the top. I did try to delete the app and redownload, but that did not work.
I have never been able to download images when using AnkiMobile (although I can see them correctly on Anki desktop). I have just ignored the problem for months, but have wanted to start using AnkiMobile to review recently.
I have tried on two residential wifi networks, cellular data, and on school wifi.
I have tried all of the troubleshooting ideas. I have also tried leaving AnkiMobile running for awhile but it always comes up with an error.
I am stumped. On the bright side, the other issues I was having have seemed to resolve. It’s now back to the same issue … I cannot see any images on my cards on Ankimobile even though all of my cards download correctly and I can see the images on Anki desktop. Weird.
I was able to fix it! I pressed synchronize and then went to the gear icon –> syncing –> media log and then just left the media log page open until it said media sync complete (it took a long time).
Just pressing synchronize in the lower right of the Ankimobile app was not syncing the media.
Now I can see images on Ankimobile 
Thanks for your help!
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