expect script not working in cron but runs successfully in terminal

Here is my expect script named as script.exp which runs successfully when executed from terminal. But it doesn't run when scheduling through cronjob.

#!/usr/bin/expect -f
set timeout -1
spawn ./sql_backup.sh
match_max 100000
expect -exact "Enter password: "
send -- "pass123\r"
expect eof

my bash script named as sql_backup.sh is:

#!/bin/bash
mysqldump -u root -p --all-databases > /home/user1/mysql/mysql-bkp.sql

and my cronjob is:

* * * * * /usr/bin/expect -f /home/user1/script.exp

Thanks

Jobs run through cron aren't run in the same runtime environment that you have on your desktop. None of your PATH changes, or other environment variable settings from ~/.bashrc are automatically propagated to your cron job. For example, there's no $DISPLAY, so GUI programs need special treatment (read man xhost).

One can set environment variables for all one's cron jobs in the crontab file Read man 5 crontab.

Look at the results of echo "=== id ===";id;echo "=== set ===";set;echo "=== env ===";env | sort;echo "=== alias ===";alias in each of your environments.

Since the command part of the crontab line is, by default, interpreted by /bin/sh, which has a simpler syntax than /bin/bash, I recommend having command be a call to a bash script (executable, mounted, starts with #!/bin/bash) which sets up the environment, then calls the desired program.