Include photos in post and publish.
In the editor I get an error that "Can't place media" when I try to include a photo. I retry but with same result. Sometimes it shows the error message "WordPressKit.wordpressorgxmlrpcapierror 0", at other times it says it may be because the photo is to big or has the wrong file format. The strange thing is that the photo is actually uploaded to the server, I can see the photo in the upload directory on the server, and in the media library in Wordpress Admin Panel.
I can't publish the post, it says it needs an internet connection, even though I already am connected to the internet.
I also get error message, "There was a problem when trying to view media" when accessing the media library in the app.
I've been in contact with my hosting provider to make sure xmlrpc is not blocked.
Create new post, include photo, try to publish.
Self hosted Wordpress site. iPhone X, iOS 13,3, WPiOS 13.8.1, Wordpress 5.3.2
The issue I had with uploading photos has been resolved to some degree by some try and error. The partly solution for me was to change the app-setting for "Maximum resolution size of uploaded photos". Some photos still "time out" and requires retrying several times before they may eventually succeed in uploading.
I had that setting set to "Full size". When I lowered the setting to 2400x2400 the problem with uploading photos partly disappeared.
I still have the problem with loading photos in the media library.
Thank you for reporting this issue!
For this type of error, it would also be helpful to note:
I will do some additional testing when I can, but wanted to ask those questions in the mean time. More soon!
The site is self hosted. I log in by entering my site address and providing username and password.
Going back through your description, I'm hearing multiple issues some of which may be related but some which may not be related:
You mentioned that updating the app-setting for "Maximum resolution size of uploaded photos" to 2400x2400 resolved items 1 to 6 — am I reading your follow-up comment correctly?
To try to test this myself, I set up a new testing site running WordPress 5.3.2 with no plugins an tried the following testing steps:
Results: I was able to add images to posts in the editor and view images in the media library in the app without any problems in my testing. This indicates that the image problems described in the original issue are most likely due to either a server misconfiguration or a plugin conflict.
Tested with WPiOS 13.9.0.2 on iPhone 6S iOS 13.3.
The problem where you are unable to view images in the media library in the app may be caused by either the host blocking communication with the app (often by placing limitations on XML-RPC, so it's good that you already checked that) or it can also be caused by a plugin conflict. The standard next step for troubleshooting a case like that would be to temporarily disable all plugins and try again and if viewing media works then re-enabling each plugin again one-at-a-time until you discover which one has a conflict. If you cannot find a conflict with any plugin then it's still possible that something on the server side is blocking the app from communicating with your site but it may be a bit harder to uncover the details in that case and I would recommend contact support for more in-depth help at that point.
If you need to contact support, it would be helpful to include:
In Slack, a user reported a similar issue:
I have a problem with the app on iOS.
A client of mine sometimes when uploading image to article, it seems that it does not upload the image, with error message “Failed to insert media. Please tap for options”, but on backend the app was uploaded it, as a result the app is uploading the image multiple times.

https://wordpress.slack.com/archives/C02RQC4LY/p1600440128000700
UPDATE: Got some more information:
In Slack, a user reported a similar issue:
This user you refer to above has now sent some logs, which includes lines such as:
2020-09-24 10:38:33:520 Error uploading media: Error Domain=WordPressKit.WordPressComRestApiError Code=7 "Invalid response from the Jetpack site" UserInfo={WordPressComRestApiErrorCodeKey=json_syntax, WordPressComRestApiErrorMessageKey=Invalid response from the Jetpack site, NSLocalizedDescription=Invalid response from the Jetpack site}
The json_syntax part makes me think that this user's error is very similar to: https://github.com/wordpress-mobile/WordPress-iOS/issues/14916 and might not be related to this issue.
I am removing the high-pri status from this issue. We will potentially add this issue to a "Media improvements" project starting in the near term.