@mostafas1990 thanks a lot. I was helpless for the last two months due to the bug. Now it is working fine.
I also wanted to report that a website: https://www.smsgatewayhub.com is distributing your plugin as theirs. (https://www.smsgatewayhub.com/wp-sms.4.0.20.zip)
Please look into it.
Thanks once again.
