Having problems installing OC - some questions

I had owncloud installed on a hosted server and it worked without a problem.

There was a problem with the php settings on the server somehow getting corrupted, and it was reset by the host - after which I started experiencing numerous problems, so I decided to install from scratch and note the problems as they occurred.

So any assistance would be appreciated.

Here are my first questions -
- Are there any known problems with running OC 9.1.4 in php 5.6.3?
- As soon as installation completed, the messages shown on the attached image 1 appeared. What could be causing these
- Why is there a report of integrity errors when the admin page does not display any - image 2
- why is there a report of 'error occurred whilst checking server setup'.

There were errors shown in the log post installation (see image 3), but they seem unrelated to the above and the system does connect to the database.

If I change from 'Files' to 'Gallery' and back, the errors relating to integrity and notifications shown in image 1 appear each time - but nothing else is added to the log file.

Any help would be appreciated, as I have relied on Owncloud since Version 8 and now can't seem to get a reliable installation.

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You have got problems to create a database. Do you want to do that on an external database server? Look after right permissions for the owncloud user.

@skriesch

The issue here is that the errors are not correct.
1. The database is created and the user 'Admin' is inserted.
2. The message shown about the code integrity error is also 'false' because no such errors are highlighted in the admin section.

That is why I am confused.

There is also another problem.
When I go to 'Apps' section, at first, there is nothing displayed. If I click either enabled or disabled I get a short list, but there is nowhere to select 'Calendar', 'Contacts' or 'Tasks' (the three I need).

Something is wrong here and I'm not sure where to start looking to resolve the problems. I never had this problem the first time I installed OC - problems only started since I upgraded from OC8 to OC9 and since then I've had numerous issues - these being the most recent.

Did you install or updrade the system? Use the upgrade instruction for an upgrade: https://doc.owncloud.org/server/9.1/admin_manual/maintenance/upgrade.html

It was a completely fresh new install.
On the same server I also installed a fresh new install of Nextcloud 11 - and that works perfectly with no errors - so I am totally confused as to why OC should have so many issues with no errors logged to indicate what is going wrong.