Yeah, there is an issue with the way desktop Outlook works as they have recently introduced strict security protocols and formatting rules in place for webcal and calendar strings which often causes it to fail or throw up a generic error above. I'll check on a Windows device, but possible fixes below in the meantime. There a few fixes: Fix 1: Classic Outlook Go through the legacy menu. In Outlook, click File in the top left corner. Click Account Settings, and then click Account Settings again from the drop-down. Click New... Paste the forum calendar link here (ensure it starts with https://, not webcal://). Give it a name and click OK. Fix 2: Uncheck "Shared Calendar Improvements" Microsoft recently changed how Outlook handles external internet feeds. A feature called "Shared Calendar Improvements" tries to aggressively convert internet feeds into Microsoft REST data, causing it to fail completely. In Outlook, go to File > Account Settings > Account Settings Under the Email tab, select the primary email address and click Change Click More Settings Uncheck the box that says "Turn on shared calendar improvements" Click Apply, restart Outlook completely, and then try adding the calendar link again. Fix 3: Clean the URL If you are copying the link straight from the forum, it might include trackable text, guest session IDs, or a trailing slash that Outlook cannot recognise as a valid .ics file type. Take the link, paste it into the web browser address bar first, and hit enter. It should instantly download an .ics file. Look at the exact URL that just downloaded the file, copy that specific string, and paste it into Outlook (Fix 1).
