"Network error" and instant 509 ban

[uNderdog101]

Describe the bug
When opening EhViewer I get no thumbnails, the fix for this is to go into a gallery and load a picture, where I will get a "network error" message, try to load the next picture and oftentimes after 2-3 attempts a pic will load normally, after which the thumbnails return and the app works as usual. But sometimes it won't load a pic and after a few more next pic attempts I get a "509" message and the image limit on e-hentai.org/home.php has gone from 0 to over 5000, giving me a temporary ban. Does the app send hundreds of image requests every time it tries to resolve a "network error"?

Edit: Just checked and after a "network error" the image limit went up 900 points.

EDIT 2: I just fixed the error on my own, turns out it was a CA certificate issue. After checking the logcat after a network error I saw a lot of entries regarding trust anchors and certificates, so I exported and installed all the certificates from exhentai directly to my tablet. The certificates had to be single certificate .pem files installed for "VPN & apps" (not wifi), after that it works as it is supposed to.

[D2Joy]

@uNderdog101 Hi, bro. I have the issue according to the logcat. May I ask how you exported all the certificates from exhentai?
I only found xxx.crt files and tried to install it. Phone said installed successful, but I can't find it in user certificates and ehviewer still does not work.

[uNderdog101]

I used the instructions here for firefox to download the single certificates and install those. Using the chain cert didn't work, so I had to install each "link" in the chain by itself as its own single certificate .pem file, but that may have been an issue with my ancient version of android.