Mobile app login problems

Hello. I’m new to Nextcloud and still learning. I have nextcloud installed on Ubuntu 18.04 using an Apache web server. I can log in on the Web interface with no issues but when I try to use the mobile app on iOS or Android it will will not log in. The weird part is it will find the server the first time I try but then when I put credentials in and press enter it doesn’t do anything. After that it will start saying server not found. I have to uninstall the app and reinstall to get it to recognize the server again but then enter credentials and it does the same thing? Has anyone else ran into this? Thanks in advance for the help