Is your member having trouble registering?
Why when he registers for a course there is a message that mentions that he has no subscription?
Go to the Profile of the member in question to make sure that there is a subscription assigned to this member. Scheduled subscriptions are not considered to be 'active' before the scheduled date.
Make sure the member does not have multiple profiles to create in the system. Check in the Free Trial tab as well as Member Management. You can delete an account that is not active.
Why when he registers for a course there is a message that mentions that he does not have access to this course?
Depending on the subscription your member has, there may be access to certain courses. Go to the Subscription tab> Subscription List> go to the subscription in question and click Edit.
There is a field concerning access to course types, check that they are all correctly selected.
Why the member is always redirected to the purchase subscription page or adding a payment method
Several reasons can affect this situation. Normally if the member is redirected to the purchase page when he goes to register in the schedule. He probably does not have access to this course, you can validate by going to check the accesses of this subscription.
Check if this member has a subscription in their profile and a payment method added. Sometimes, trying to log into the profile yourself can fix the problem.