Error Connecting To Polar's Regtest Node

[Mimble-Wimble]

Attempting to connect to Polar's regtest node with:

docker run \
  -v /Users/user/electrumx:/data \
  -e DAEMON_URL=polaruser:polarpass@127.0.0.1:18443 \
  -e COIN=BitcoinSegwit \
  -e NET=regtest \
  -p 50002:50002 \
  -p 127.0.0.1:8000:8000 \
  lukechilds/electrumx

Returns the error:

INFO:electrumx:ElectrumX server starting
INFO:electrumx:logging level: INFO
INFO:Controller:Python version: 3.7.9 (default, Dec 18 2020, 05:56:48)  [GCC 9.3.0]
INFO:Controller:software version: ElectrumX 1.16.0
INFO:Controller:aiorpcX version: 0.18.7
INFO:Controller:supported protocol versions: 1.4-1.4.2
INFO:Controller:event loop policy: <uvloop.EventLoopPolicy object at 0x7f4968ff9990>
INFO:Controller:reorg limit is 8,000 blocks
INFO:Daemon:daemon #1 at 127.0.0.1:18443/ (current)
INFO:DB:switching current directory to /data
INFO:DB:using leveldb for DB backend
ERROR:Daemon:connection problem - check your daemon is running.  Retrying occasionally...

Steps to Reproduce:

• Install and run v1.3.0 of Polar
• Create and start the default regtest node in Polar.
• Attempt to connect docker-electrumx using Polar's credentials with:

docker run \
  -v /Users/user/electrumx:/data \
  -e DAEMON_URL=polaruser:polarpass@127.0.0.1:18443 \
  -e COIN=BitcoinSegwit \
  -e NET=regtest \
  -p 50002:50002 \
  -p 127.0.0.1:8000:8000 \
  lukechilds/electrumx

[tanx]

@Mimble-Wimble have you solved the issue? I'm getting the same error:

ERROR:Daemon:connection problem - check your daemon is running.  Retrying occasionally...

[Jasonvdb]

Possible solution in this comment