While sending some mails I am getting a bounce back email saying my sending IP “46.101.181.93” is banned.
You aren’t on any blacklists and your IP isn’t a dynamic ADSL range. Who is telling you you are banned?
I got this mail when sending an email
This is the mail system at host box.ehsconsultantsgroup.org.
I’m sorry to have to inform you that your message could not
be delivered to one or more recipients. It’s attached below.
For further assistance, please send mail to postmaster.
host
[216.32.180.10]
said: 550 5.7.606 Access denied, banned sending IP [46.101.181.93].
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
Micro$oft, grrr. But usually they have a URL for problem resolution in the bounce message … I am not seeing that in what you posted.
Your DNS set-up is also not proper. Are you using the box or NameCheaphosting for DNS? You cannot use both. Actually, NameCheaphosting DNS is not answering, but it is not certain why it is even being referenced.
Thanks for the reply. Actually I am hosting my site on name cheap and only email server is through mail in a box on a digital ocean server.
I have checked my mail server settings and found out that SPF records are not properly set, maybe that’s why we are unable to send mail and our mails considered as spam. Here I am adding report link and a image of my setting for mail-in-box please take a look
Still I wonder about this …
I am hosting my website on a Namecheap server and email server is hosted on Digital Ocean box with mail-in-a-box but I may have made a mistake somewhere and I am unable to resolve it
Ok, but my question is where are you INTENDING to host your DNS? I see where your website is hosted and where your email is hosted. I see where your DNS is being answered from but I also see other NS records for your domain. Why? That is the mystery that I am trying to understand.
OK, I think I have found the answer. NameCheapHosting has set the TTL on their ns records to 21 DAYS!!! Was NameCheap also hosting your DNS before you installed MiaB? If so, they are the problem it appears. 21 Fu!T&&*( DAYS! Unbelievable! This is my best guess at this point, but it is the ONLY thing I can come up with. So please confirm my theory by sharing who hosted your DNS prior to MIAB. Also when did you switch to MiaB? (So we know when 21 days is up)
Your SPF is failing because the DNS is showing the mail.ehsconsultantsgroup.org is your MX record on the records being returned by dns2.namecheaphosting.com. In fact, your MX record should be returning box.ehsconsultantsgroup.org which it will when the 21 days are up. 
Sorry for replying so late. I have checked my TTL it is set on 1200 and SPF record issue is also resolved.
I am adding how I resolved the issue here so that others might get help with this topic. For hosting mail server and domain on different server we have to change IP address of mail.example.com to the IP address of our mail server and on the mail server end we have to use custom DNS setting to set your domain name server record(NS). You can either use your name record in secondary name server section or you can add an A record with IP of your name server using custom DNS setting.
If someone needs any help regarding this issue they can post here. I will be happy to help.