Use this option if your email is hosted on Office365 and you would like to use the same to send out calendar invites. 


Important Note before proceeding with O365 Integration:  

1. Do not use this option if you use "Outlook" email application however your Email is hosted and managed by other service provider and not Office365

2. Do not use this option if you use free email service provided by outlook.com or hotmail.com (e.g. your email address ends in @outlook.com or @hotmail.com) 


3. Before proceeding please note: We (Let's Calendar) DO NOT recommend usage of Office 365 as the default method to send bulk calendar invites. 


Essentially Office365 or O365 is more used for corporate / official communication and not for mass emailing by design. Hence any high volume emails triggered from Office365 infrastructure can impact your email capabilities as well as SPAM ratings. 


4. Understand O365 sending capabilities and sending limits - As we mentioned in point #3 above, O365 is a business email service and is not made for bulk email or calendar invite sending and to ensure it's infrastructure and services are not misused by spammers, Microsoft O365 has implemented certain sending rate limits in each and every O365 account, unless your IT team has manually changed these configuration and worked with O365 to increase these limits. Please check this help article from Microsoft O365, as per this the default restrictions (from Microsoft O365 side) apply on your O365 account will be as under - 


  • Per minute sending limit - 30 messages per sending email identity
  • Per email/calendar invite sending limit - 500 email address (Contacts) per sending email identity (Can be increased to 1000 contacts by your IT team manually by logging into O365 admin panel)
  • Per day max messages limit - 10,000 total messages per sending email identity per 24 hrs


Ideally you should use Mass email applications like Sendgrid, Mailgun, Sendinblue etc for sending Mass Calendar Invites, as these applications are designed and geared to handle bulk volume based email and calendar invite sending. 


Considering your recognize the above and wish to continue using your Office 365 email as SMTP option, please proceed as under - 


Step 1 - Login to Let's Calendar account, and navigate to Settings -> SMTP Config -> https://panel.letscalendar.com/smtp


Step 2 - Under Add SMTP Configuration -> Mailing Service -> Select Dropdown and select Office 365


Step 3 - Click on "Sign in to Office 365" button 



Step 4 - Follow on-screen instructions to sign into your Office 365 account 

(Don't worry the sign-in box is directly being served by Office 365 and when you enter your user id / email address and password, you are entering this in secure office 365 login infrastructure as well as domain. The login credentials are not shared with anyone else including Let's Calendar) 


Step 5 - After successful sign-in, kindly accept and authorize Let's Calendar App (Managed by our parent company Manomay Informatics) to access your info (Let this app access your info?) -> Click on YES



Step 6 - Follow on-screen instructions if any to complete authentication and return to Let's Calendar screen with a "Success" Message


That's it, you are now ready to use your email address hosted on office 365 email to send calendar invites.