Bitcoin Core v0.21 RPC credentials going bad I have tried to upgrade to bitcoin core 0.21 but things are not going good. I need some help.
I'm using Debian Buster.
I was using bitcoin core 0.20.1 before.
The folder locations are as I have in my config file:
dbbatchsize=4294967000
dbcache=12288
par=1 -daemon
server=1
maxtxfee=0.00002000
mintxfee=0.00000002

\# Options only for mainnet
[main]
conf=/media/WdElements/blockchain-backup/bitcoin.conf
datadir=/media/WdElements/blockchain-backup
debug=net
debug=rpc
debuglogfile=/media/WdElements/blockchain-backup/debug.log
addresstype=bech32
changetype=bech32
txindex=1
listen=1

When I start bitcoin daemon I see the following output:
2021-01-24T15:24:36Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:36Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:41Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:41Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:45Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:45Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:49Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:49Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:53Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:24:53Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:58Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146
2021-01-24T15:24:58Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:25:02Z ThreadRPCServer incorrect password attempt from [::1]:34362
2021-01-24T15:25:02Z ThreadRPCServer incorrect password attempt from 127.0.0.1:36146

I already tried to generate my RPC credentials from ./share/rpcauth/ python plugin like this:
$ python3 rpcauth.py btc-user
String to be appended to bitcoin.conf:
rpcauth=btc-user:[REPLACEDHASH]
Your password:
[REPLACEDPSSWD]

and paste the first line into bitcoin.conf  like this:
dbbatchsize=4294967000
dbcache=12288
par=1 -daemon
server=1
rpcauth=btc-user:[REPLACEDHASH]
maxtxfee=0.00002000
mintxfee=0.00000002

\# Options only for mainnet
[main]
conf=/media/WdElements/blockchain-backup/bitcoin.conf
datadir=/media/WdElements/blockchain-backup
debug=net
debug=rpc
debuglogfile=/media/WdElements/blockchain-backup/debug.log
addresstype=bech32
changetype=bech32
txindex=1
listen=1

but I still get the same error messages when I start bitcoind as bitcoind:
2021-01-24T15:32:19Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:19Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:23Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:23Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:27Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:27Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:31Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:31Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:36Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:36Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:40Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:40Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690
2021-01-24T15:32:44Z ThreadRPCServer incorrect password attempt from [::1]:35906
2021-01-24T15:32:44Z ThreadRPCServer incorrect password attempt from 127.0.0.1:37690

Anyone can help me figuring out what might I be doing wrong?
Ok, I managed to find the culprit. It's actually an application I have running in the background that I simply completely forgot about it and it is trying to access to the RPC interface and as I have never paid too much attention to it, I think I never setup anything related to RPC in it. So, most probably that's the problem.
I used netstat -p -at and ps -ef to figure out what exactly was interacting with bitcoin core daemon.
Thanks every one. I think this one is solved.
Psy