Thanks for letting me know about the topic issue in this category - I'll work on getting that resolved.
Regarding issues with Belong 1.1.4 and WHMCS 5.2.2, I'm actually a little surprised there would be any issues, as the integration is pretty minimal really as far as logging in etc.
This error is only coming up when you view the pages from the Client Area? Very unusual... I'll look into it some, but I'm going to roll out Belong 2.0 next week, so if you can hold tight for just a few more days, we'll have a brand new interface and product ready to go for WHMCS v5.2.2.
I do apologize for the delay in getting this resolved - for the benefit of the community, I'll post the solution here so others can find the answer in the event of a similar issue:
After installing Belong into WHMCS, entering the license fails, the license isn't saved and is reported as invalid. No settings can be saved and the license doesn't appear to be reloaded when coming back to the license page.
This is caused by activating the Belong addon before activating the Dunamis Framework addon. Belong requires the Dunamis Framework to be activated so the database can be accessed, without it, the database tables are not installed and nothing can be saved in the Belong product.
To correct this:
1) Log into WHMCS admin area and access the Addon Modules area under Setup > Addon Modules
2) Deactivate Belong
3) Deactivate Dunamis
4) Enable Dunamis
5) Enable Belong
6) Enter your license into Belong under Addons > Belong > License and you should be all set