Have you seen this https://www.fastcomet.com/tutorials/oxwall

I personally have never used cloud for oxwall but as i understand it, there is alittle different configuration required, someone correct me if i am wrong please. 

Please let us know if there are any errors at all in your error log.

Also the error when you try to access the site means your table is missing from the database 

ow_notifications_notification

you need to put this table back in your DB, you can find the structure of the table in the install folder of oxwall. 

put that table back and then see what happens

CREATE TABLE `ow_notifications_notification` (  `id` int(11) NOT NULL AUTO_INCREMENT,  `entityType` varchar(255) NOT NULL,  `entityId` varchar(64) NOT NULL,  `action` varchar(255) NOT NULL,  `userId` int(11) NOT NULL,  `pluginKey` varchar(255) NOT NULL,  `timeStamp` int(11) NOT NULL,  `viewed` int(11) NOT NULL DEFAULT '0',  `sent` tinyint(4) NOT NULL DEFAULT '0',  `active` tinyint(4) NOT NULL DEFAULT '1',  `data` text,  PRIMARY KEY (`id`),  UNIQUE KEY `entityType` (`entityType`,`entityId`,`userId`),  KEY `timeStamp` (`timeStamp`),  KEY `userId` (`userId`)) ENGINE=MyISAM AUTO_INCREMENT=25 DEFAULT CHARSET=utf8;