usually comes to 2 things:

1. router isn't well integrated

for router integration avoid things like stopping/starting repeatedly, let the router run for a while and learn about more peers. make this go faster by maxing exploratory tunnels 16/16 and go download some popular torrents.

2. postman has you ratelimited

tracker2 is probably the most visible/popular site in i2p so it's a frequent target for attacks, so it's protections are more aggressive than some other sites. to subvert these protections simply start a new browser session/b32 destination for your http tunnel. you will then appear as a different entity to tracker2.

I'm having similar issues on my Phone. I can load the disclaimer but am unable to proceed.

also, I'm trying to upload to postman for the first time and am unable to as my requests keep getting denied. I have submitted this as a Ticket.

avoid restarting the i2p router like that if you're not doing graceful shutdown, peers don't like that

get a new http destination by doing Reload tunnels configuration, you may want a new browser session. there is a lot of ratelimiting and other protections going on

I had certain torrents to upload but I am not able to access postman tracker, it just never loads, keeps on buffering for eternity and then suddenly says rate-limit achieved try after 60??
like what the fuck??
I have gigabit connection so aint no way it is not working.
i have repeatedly started and stopped I2PD with 1 minute interval between every restart and then for 2 minutes allowed the router to explore tunnels and it says 43% tunnels rate.
it is far better for any connection and any website then why does this postman does not work?