Unable to delete calendar spam

Hopefully this official support document helps:

Delete calendars and events on iPhone - Apple Support

A similar discussion is available here:

Unwanted / Spam Calendar Event will not D… - Apple Community

I did a quick search and found that there are dozens of discussions on Microsoft discussion forums and this Apple Community of other people experiencing the same thing. The common thread is various Microsoft-hosted accounts like Hotmail. Most solutions were folks report success involve using Outlook as the tool to resolve the issue. In Outlook, you can first make a setting to block future calendar spam, and then you can evidentially delete the events. One additional suggestion I found is that you should find and delete all traces of the email invites as well (from Trash, Spam, or whatever mailbox they ended up in). The following article has several links that detail how to delete the events and also stop it from reoccurring:

https://answers.microsoft.com/en-us/outlook_com/forum/all/how-to-delete-and-prevent-spam-invites-in-my/1394ff95-3e39-47ce-b86b-0d2f76d9e515

Because you may not have access to Microsoft Outlook on a computer, I recommend that you instead login to "Outlook.com" using your Hotmail user account. I recommend doing this from a desktop/laptop computer. From that web version or Outlook, try the following to prevent the issue:

1. Log on to Outlook.com
2. Click the Settings "cog" icon in the upper right
3. You might need to then click on "View all Outlook settings" (may or may not be necessary for your account)
4. Click "Calendar" on the left sidebar
5. Click on “Events from email” (note that there also seems to be frequent reports of this screen being blank for some users)
6. Turn the settings for each type of invite to “Don’t show event summaries in email or on my calendar”

Here is the official Microsoft support article about these settings -- scroll down to see how from Outlook.com web version (https://support.microsoft.com/en-us/office/automatically-add-events-from-your-email-to-your-calendar-32e5cf0c-3e65-4870-9ff9-df3683d3fc97). I hope that works for you because, I tried the same in my Microsoft 365 account and ran into another frequently reported Microsoft issue where the entire “Events from email” setting page is blank.

I suspect you may have a hotmail, outlook, or other Microsoft exchange account. If that is the case, their servers have once again been swamped with spam calendar events. The Calendar app on your phone simply syncs the events that are on those servers. This is not the first time Microsoft has had a problem with these.

If you do not use the calendar for that email account you are using, then you just need to stop syncing the Calendar for that account and they will go away. Just stick with the iCloud calendar and you should have no problem. When people add the mail accounts, they don't realize that they are also adding the calendar or contacts associated with the email. You can view what those accounts are syncing by going into settings and choose the Calendar. You don't want to remove the account, just flip the switch for syncing the calendar on that account.

See if you can use a web browser to log into that particular email/calendar account and remove the events from there. In addition, that is where you should find any options that may prevent calendar spam such as settings that prevent anyone from adding calendar events unless they are in your contacts, or unless you accept. It all depends on the type of account.

Seasidebella wrote:

That all makes sense - thank you so much!

Your welcome. Microsoft has had this problem come and go for a very long time. Attempts to stop it on their servers work for a short time, then it will be a problem again. The best thing you can do is completely remove the syncing with those servers and manage your Calendar events on iCloud.

I have one more suggestion for possible immediate relief from calendar spam that stops short of just removing the Hotmail account completely from iOS. If you don't use Hotmail for calendars at all, then just disable the calendar in iOS:

1. Settings > Apps > Calendar, then tap Calendar Accounts
2. Tap the Hotmail account
3. Toggle off "Calendars"

Yes that was what is recommended. No need to remove the hotmail email account, just need to quit syncing the Calendar associated with that account.