transaction index disabled is logged when the txindex=1 or -txindex flag is not set. If it was once indexed, and you don’t pass that flag, then bitcoind will prevent you from accidentally rebuilding the database without the indexes unless you explicitly tell it to with -reindex. Check your bitcoin.conf file and the startup script. Alternatively, try adding -txindex to /etc/systemd/system/bitcoind.service where bitcoind is called:
ExecStart=/usr/local/bin/bitcoind -txindex -daemon -conf=/home/bitcoin/.bitcoin/bitcoin.conf -pid=/home/bitcoin/.bitcoin/bitcoind.pid
