Hi John,
From your description, when you send mail from g.a.johnprabhu@gmail.com to john@ijmitsolution.com, an error occurs and mail failed to delivery to Office 365 mail account. After reviewing the DNS record about the domain ijmitsolution.com, I find there are three MX records with the same priority. I suggest we set MX record with Priority 0 to point to Office 365, and set other priority value higher than this one. The related MX record setting we can refer to DNS settings in Office 365 Portal.
In general, any DNS record changes updated in the DNS system can take from 15 minutes to 72 hours to be propagated. So if you just update the MX record, please wait for 24 hours to see if any improvement.
Thanks,
Johnny Zhang