ElectrumX dogecoin doesn't work

Server crashes after synchronization with "Killed" error.

ElectrumX log:

INFO:electrumx:ElectrumX server starting
WARNING:Env:lowered maximum sessions from 1,000 to 674 because your open file limit is 1,024
INFO:electrumx:logging level: INFO
INFO:Controller:Python version: 3.9.1 (default, Feb  1 2021, 09:08:06)  [GCC 7.5.0]
INFO:Controller:software version: ElectrumX 1.16.0
INFO:Controller:aiorpcX version: 0.18.5
INFO:Controller:supported protocol versions: 1.4-1.4.2
INFO:Controller:event loop policy: None
INFO:Controller:reorg limit is 2,000 blocks
INFO:Daemon:daemon #1 at 127.0.0.1:22555/ (current)
INFO:DB:switching current directory to /home/ubuntu/db
INFO:DB:using leveldb for DB backend
INFO:DB:opened UTXO DB (for sync: True)
INFO:DB:UTXO DB version: 8
INFO:DB:coin: Dogecoin
INFO:DB:network: mainnet
INFO:DB:height: 3,592,619
INFO:DB:tip: d69cd535b31679cd5c505ca4ad40e5236a67a619844294af9279261bf3939e72
INFO:DB:tx count: 70,575,752
INFO:DB:flushing DB cache at 500 MB
INFO:History:history DB version: 1
INFO:History:flush count: 156
INFO:Prefetcher:catching up to daemon height 3,593,544 (925 blocks behind)
INFO:BlockProcessor:our height: 3,592,629 daemon: 3,593,544 UTXOs 0MB hist 0MB
INFO:BlockProcessor:processed 10 blocks size 0.22 MB in 2.4s
INFO:BlockProcessor:processed 700 blocks size 11.12 MB in 9.3s
INFO:BlockProcessor:processed 215 blocks size 4.27 MB in 1.5s
INFO:BlockProcessor:caught up to height 3593544
INFO:DB:flushed filesystem data in 0.01s
INFO:History:flushed history in 0.2s for 61,712 addrs
INFO:DB:flushed 925 blocks with 27,817 txs, 43,144 UTXO adds, 45,925 spends in 0.2s, committing...
INFO:DB:flush #157 took 0.5s.  Height 3,593,544 txs: 70,603,569 (+27,817)
INFO:DB:tx/sec since genesis: 6,957, since last flush: 1,845
INFO:DB:sync time: 02h 49m 07s  ETA: 00s
INFO:DB:closing DBs to re-open for serving
INFO:DB:opened UTXO DB (for sync: False)
INFO:DB:UTXO DB version: 8
INFO:DB:coin: Dogecoin
INFO:DB:network: mainnet
INFO:DB:height: 3,593,544
INFO:DB:tip: 5f5beb8d2d61f519d62a1b42fadfcf2b4814a9e53c5e8533643f536e087f0ea2
INFO:DB:tx count: 70,603,569
INFO:History:history DB version: 1
INFO:History:flush count: 157
INFO:DB:deleted 925 stale undo entries
INFO:DB:populating header merkle cache...
INFO:MemPool:beginning processing of daemon mempool.  This can take some time...
INFO:SessionManager:max session count: 674
INFO:SessionManager:session timeout: 600 seconds
INFO:SessionManager:session cost hard limit 10,000
INFO:SessionManager:session cost soft limit 1,000
INFO:SessionManager:bandwidth unit cost 5,000
INFO:SessionManager:request sleep 2,500ms
INFO:SessionManager:request timeout 30s
INFO:SessionManager:initial concurrent 10
INFO:SessionManager:max response size 10,000,000 bytes
INFO:MemPool:compact fee histogram: []
INFO:MemPool:synced in 0.28s
INFO:MemPool:182 txs 0.07 MB touching 581 addresses
INFO:SessionManager:TCP server listening on all_interfaces:50001
INFO:PeerManager:peer discovery: ON
INFO:PeerManager:announce ourself: True
INFO:PeerManager:my clearnet self: None
INFO:PeerManager:force use of proxy: False
INFO:PeerManager:beginning peer discovery...
INFO:PeerManager:trying to detect proxy on "localhost" ports [9050, 9150, 1080]
INFO:PeerManager:no proxy detected, will try later
Killed

ElectrumX config:

export DAEMON_URL=http://*:*@127.0.0.1:22555/
export DB_DIRECTORY=/home/ubuntu/db
export USERNAME=ubuntu
export COIN=Dogecoin
export NET=mainnet
export CACHE_MB=500
export SERVICES=tcp://:50001

Could there be a problem with coin setting in coin.py?

Start by reproducing the failure with the supplied ElectrumX configuration and logs, then inspect coin.py and the startup path after synchronization completes. Done means identifying why the process is killed and documenting a confirmed configuration or code change that prevents the crash.