Hi,
Please troubleshoot using the following steps.
1) Please check that you are using the correct email address and password to login
2) If you are using a cache plugin, please do not cache client-login page or any page related to Projectopia. Please clear your cache plugin’s cache content.
3) Please clear your browser history, and reload client-login page and you should be able to login.
If the above information does not help, please use the steps in the following documentation to check for conflict.
https://projectopia.io/docs41/troubleshooting-steps-for-cache-plugin-conflict-and-theme-conflict/
By the way, please open a new thread if you have a new issue.
Thank you