Calendar overlay suddenly has no links

Question

We built a calendar with 6 overlayed calendars.

It's been running for months, we didn't do any modification to it recently. It is used daily by about 10 users.

This morning, the links in the calendar overlay (left navigation panel) are not clickable anymore. I can't click on "Calendars in view", but I cannot click on the calendars' names to get to a specific calendar anymore.

Here's what the panel looks like:

<div class="ms-acal-apanel">
<ul>
    <li><a class="ms-acal-apanel-title" href="/smt/else/_layouts/15/aggregationsettings.aspx?List={774142C0-C4F7-44E1-A230-35D4C9167FE1}&amp;View={45977982-02CA-5007-87BE-CDD4BEDD346}&amp;Source=%2Fsmt%else%2FLists%2Fsmth%2Fcalendar%2Easpx"><img src="/_layouts/15/images/itevent.png" alt="Calendars in view" title="Calendars in view" border="0"><span>Calendars in view</span></a>
        <ul>
            <li><span class="ms-acal-apanel-item ms-acal-apanel-color"><span>Calendar 1</span></span></li>
            <li><span class="ms-acal-apanel-item ms-acal-apanel-color1"><span>Calendar 2</span></span></li>
            <li><span class="ms-acal-apanel-item ms-acal-apanel-color2"><span>Calendar 3</span></span></li>
            <li><span class="ms-acal-apanel-item ms-acal-apanel-color5"><span>Calendar 4</span></span></li>
            <li><span class="ms-acal-apanel-item ms-acal-apanel-color6"><span>Calendar 5</span></span></li>
            <li><span class="ms-acal-apanel-item ms-acal-apanel-color7"><span>Calendar 6</span></span></li>
        </ul>
    </li>
</ul>

It seems like the anchor tags all disappeared. I found someone else with the issue, but it looks like time solved their trouble.

How can I have the calendar overlay contain links again ? Is there a cache I can delete that could solve this issue ?

Answer 1

It seems to be caused by an earlier update to SharePoint (October 2019 seem's to be the case). The problem is reported for SharePoint 2016 to.

There is a fix available in the SharePoint 2013 foundation cumulative update this month.

This update fixes the following issues:

• You are unable to access Office Add-Ins from a document that is opened in a browser when they are provided by the SharePoint App Catalog Service.
• Calendar overlay items that are listed under Calendars in View are not clickable.

January 14, 2020, update for SharePoint Foundation 2013 (KB4484233)