Blank screen after installing an app

after installing sharepoint app ,I get blank screen when access a nextcloud from browser.
I get this error:
{"reqId":"IKfg7MkkTAj8bMNjby2V","level":3,"time":"February 03, 2020 16:36:02","remoteAddr":"","user":"--","app":"PHP","method":"","url":"--","message":"Interface 'OCA\\Files_External\\Lib\\Config\\IBackendProvider' not found at \/var\/www\/nextcloud\/apps\/sharepoint\/lib\/Backend\/Provider.php#31","userAgent":"--","version":""}
why get this error?
Maybe because of Bug if not (we arrange it to disabled if show there is error) then when install an app like facing error if enable it, look like that show for me as disable button with show message that cause error if enable that app,I’m not sure if the error caused before press the (disable button) or after it.
Best Regards

I get the soulution From:

update oc_appconfig set configvalue="no" WHERE appid="storage_charts" AND configkey="enabled";

so was there problem because of sharepoint app (you can get the name from directory in apps or by logs)
so the command should be :

update oc_appconfig set configvalue="no" WHERE appid="sharepoint" AND configkey="enabled";

make sure to take backup of database.
Best Regards

occ app:disable appname is the prefered way of disabling an app.

And it seems like you installed the sharepoint backend without enableing external storage first. Seems like the sharepoint backend doesnt comlain that external storage is not available and crashes instead

Look like php stopped so there was blank screen from browser.
Yea,look like as you said.