The progressive tense isn't grammatically wrong, but it becomes what we call lazy or imprecise writing. If we think "in the process of," we'll probably use the tense well. It means some action is ongoing and uses a participle (an active verb with an –ing ending).
It's correct to use the progressive tense to express frequent action: We will be going to church Sunday. But it's just as easy to use the future tense: We will go to church Sunday.
Present Progressive tense indicates an action that takes place right now. It uses a "to be" verb and the present participle. (a) I am walking to the store. (b) He is lecturing to the class.
Use the simple past: I walked to the store. He lectured to the class.
Indifferent writers use the present progressive for future action: (a) My brother is graduating next month. (b) I will be visiting Canada in September.
Careful writers use the future tense: (a) My brother will graduate next month. (b) I will visit Canada in September.
Past Progressive tense refers to an action that took place in the past and is formed with a "to be" verb and the past participle. I was eating lunch with my friends. The past-progressive form implies an interruption to the action: While I was eating my lunch, the phone rang.
The weakness of using the past progressive tense becomes obvious when we use the passive-progressive form. Compare: (a) She was being robbed on Main Street. That construction implies that someone interrupted the in-progress robbery. (b) She was robbed on Main Street. The crime was committed and the culprit vanished.
Make your meaning clear by using simple past, present, and future tenses.