365 Sync Issues - Error Synching Appointments 400

[supportedge]

Hi, I was wonder if anyone else has had this issue, or any advice.

Only a few months after I purchased the m365 (Office 365) sync integration all went pear shaped. I spent a few hours trying to resolve it when it first happened, and now about 3 months after it failed, I’ve spent another hour on the problem.

I know i should have done something sooner about it, but I was just so frustrated by something costing so much and failing within 3 month, plus i don't have the time to mess with stuff like this. I just need the software I purchase to work.

Now I have more time, if anyone can help me get it working that would be great.

If i leave sync active i get: (to avoid this constantly popping up I’ve turned of sync for now')
'Error Synching Appointments 400' 'the token has expired due to inactivity'

If I start from scratch and try to re-connect any accounts, first thing I get is a certificate error 'the name on the security certificate is invalid or does not match the name of the site'. When I 'view cert' for some reason is shows the cert of our RDP server?

After all this this I get a HTTP/1.1 400 Bad Request error.

Thanks in advance

Ben

[Support Team]

Re: 365 Sync Issues - Error Synching Appointments 400

Thank you for posting this.

Microsoft 365 requires to re-authorize the application every 6 months or so, therefore you received the error 'the token has expired due to inactivity'' *and re-selecting the 365 calendar to sync with is needed. This is performed under the Tools > Options > Outlook/365 tab.

The same is required when the password for 365 account is changed.
With the latest version just after this error/notification, you will be prompted with the connection wizard.

As for the error "HTTP/1.1 400 Bad Request" *- It means that the request to connect to Office 365 servers got blocked and it is usually related to a firewall issue. Turning the firewall/antivirus off should solve this
As an alternative, you can try to configure the sync using another PC.

Regarding the certificate pop up you refer to - We have received a few similar reports while trying to configure the sync using an RDP connection and what helped was to cancel the certificate prompt that pointed the the internal resource.

Hope this helps and in case needed, feel free to also contact us at support@...

[supportedge]

Re: 365 Sync Issues - Error Synching Appointments 400

I wasn't required to make any changes to our firewall/av config. for us cancelling, pressing [X] on the cert. pop-up got the process going and the calendars syncing again