I recently become a member just to read grimgar but im always stuck on Rendering Spline or something using the app everytime i would read the preview. then i go browser works just fine, but then i can only read part 1 of grimgar for ex lvl 1 part 1up to lvl 10 part 1 i cant seem to find where the hell is part 2
@jose-hizole It's because the service let you read parts from volume which are being translated right now or have been published not long ago. So right now they are translating Vol13 (3/8 done) so you can read and a new part is published each week, and vol 12 and 11 which were published not long ago are still readable for a time. But all the one before that aren't readable anymore outside of parts 1 which are allway available as preview. If you want to read the first volume you have 3 choices: 1) wait for a Grimgar catchup where all the part from all the vol are readable for a month usualy the serie in catchup change each month. 2) buy them from Amazon, google book, kobo, ... 3) buy them directly from J-novel club the advantage is that those e-book are DRM-free and have some premium bonus the one in book 1-3 are just picture but after it's bonus short stories.
Conserning the app it may be a bug, personaly it work just fine.
As per https://j-novel.club/faq being a member gives you access to pre-production releases but only until the novel has been published (at which point you need to buy the novel). I have premium membership to get premium credits to buy the e-books at discounted rates, and for Grimgar these premium ebooks tend to include bonus short stories as noted by @Raitoiro
If you are reading a preview or pre-production chapter and it is taking forever to load then you may need to change your settings to enter 'simple' mode due to a bug in how the app loads graphics on some devices.