Nextcloud version (eg, 10.0.2): 9.0.56
Operating system and version (eg, Ubuntu 16.04): CentOS 7.3
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4.6
PHP version (eg, 5.6): php 5.6
Is this the first time you’ve seen this error and can you replicate it?: yes
The issue you are facing:
I have a user for whom the “Share with you” link in the web application hungs forever. I tried to upgrade to 10.0.3 but that hung forever too, so I fear that there is something in the database defective with this user. Any idea how to debug that?
The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
The output of your Apache/nginx/system log in /var/log/____:
Remember, this information may be requested if it isn’t supplied; for fastest response please provide as much as you can 
Feel free to use a pastebin service, otherwise log files can be indented with 4 spaces on each line to present them in a friendlier way on the forum.