Vlang SMTP not working properly

[AritraBanik08]

I am making a bed & breakfast website using vlang. I am using the net.smtp package and it is showing the error

V panic: Received invalid response from server
v hash: 5b1b2cc
0   main                                0x00000001027e115c src__mails__my_smtp + 784
1   main                                0x00000001027ddc9c main__App_summary + 52
2   main                                0x00000001027daf68 vweb__handle_route_T_main__App + 22596
3   main                                0x00000001027d5674 vweb__handle_conn_T_main__App + 2840
4   main                                0x00000001027e0cf8 vweb__Worker_T_main__App_process_incomming_requests_T_main__App + 272
5   main                                0x0000000102745a08 vweb__Worker_T_main__App_process_incomming_requests_T_main__App_thread_wrapper + 36
6   main                                0x00000001027f8d14 GC_inner_start_routine + 92
7   main                                0x00000001027f69c8 GC_call_with_stack_base + 36
8   libsystem_pthread.dylib             0x000000018be1f034 _pthread_start + 136
9   libsystem_pthread.dylib             0x000000018be19e3c thread_start + 8

It is working properly when used in my main function but crashing every time without fail when used in other functions. For more context check my code at here
Thank you for your king help.