Hi,
Vendor calendars are not syncing with rental hive if the external calendar is set to a timezeone like GMT. It only works when it is set to a City e.g. London
We checked this issue from our side, and it seems okay. Please provide more details regarding this issue (e.g., your actions step by step with screenshots, etc.). This will help us to reproduce and resolve the issue faster. Also, please disable third-party plugins and customizations (if there are any) and check if this issue persists. If you use a caching plugin, make sure that caching is disabled for logged-in users.
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We received your link and checked it out in more detail. Most likely, your calendar describes the external timezone in the wrong format, this format is not accepted in PHP (what WordPress is made on). Therefore, I recommend that you check in your third-party calendar whether there is an option to change the timezone since it is now GMT Standard Time and should be UTC, for example. Here you can see the list of allowed ones: PHP Timezones