Using Ubuntu 16.04LTS I upgraded to 18.04LTS. Nextcloud no longer works stating…
"Your webserver seems to be not configured to use PHP or PHP is not installed. " etc.
Is this recoverable?
Apache2 is running, php is installed but MySql may have an issue.
Any input would be helpful.
Please search the web regarding ubuntu and mysql to solve basic db stuff.
since we can not magically know what went wrong, i suggest you use the template and give as much information as possible. Overall Version numbers of virtually everything involved are mandatory.
As a first guess: Play the info.php game and post your output here (sans private information). From my expiereinece, PHP is a little bitch when upgading an entire system. Maybe the DB Connector module is missing or the version got upgaded and you need to fondle it together again. The DB itself should not have been touched afaik.
As a gerneral guideline: Before upgrading, always make a full Backup or Snapshot or whatever is applicable to you, so you have a path back to a functioning system in case shit breaks.