Can't edit home page

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I received these error messages:
[02-Apr-2021 23:02:48] PHP Fatal error: Call to a member function query() on a non-object in /home/oldjuggy/vcs.education/updates/concrete5.6.3.5_remote_updater/concrete/core/models/package.php on line 66
[03-Apr-2021 15:46:26] PHP Fatal error: Call to undefined method DOMElement::getLineNo() in /home/oldjuggy/vcs.education/updates/concrete5.6.3.5_remote_updater/concrete/libraries/3rdparty/simplepie.php on line 16528
One of three RSS feeds on my home page went down and locked out the editor. But when I sign in the other pages are editable. I'm reluctant to remove the RSS block in case the whole site goes down.
Is there an easy fix?
Thanks for any help.
Mal