ALSO POSSIBLE: A Problem Resolved Problem

There was another music problem when uploading a new video to YouTube.

I used the Jianying APPapp to add music to my videos because it offers lots of free music, for which it has already paid copyright fees.

But sometimes, those don't cover the copyright on YouTubeOPTION A: However, some of the music is not covered by YouTube's copyright rules.¶
OPTION B: However, YouTube's copyright rules do not cover some of the audio content.

MY GUESS: When YouTube found the music problem, itpointed out the copyright problem, I was hoping they would offer some replaceable opalternative solutions.

It'sYouTube's suggested sources were nice and thoughtful, but it' was difficult to find an alternative that matches my feelings.

I found that there were some free pieces of music on YouTube that we could download too.

I downloaded some that matched my feelings and decided to use them to replace my original music before uploading videos to YouTube.

Then the musical problem was resolved, even though my videos on YouTube would just have those few music choices.

Also.,

NOTE: Change the period (.) to a comma (,) ....

Iif you watch my video here https://www.youtube.com/shorts/3vZSN4Psv5c and enjoy it, would you please press the "like" button for me?

There was / I encountered / I had / I ran into another music problem when (or: while) uploading a new video to YouTube.

We tend to prefer active voice (“I did something”) instead of passive (“there was something”) in English.

I use the Jianying APPapp to add music to my videos because it offers lots of free music for which {it has | they have} already paid the copyright fees.

In English, “app” isn’t capitalized. It’s short for “application” (as in “computer application” (software program)).

It was really annoying because every time I chose the music that matched my feelings in the video., when YouTube found…

I think this works better when combined with the next sentence.

W…when YouTube found a (copyright) problem with the music problem, it would {offer some replaceablement options | suggest some replacements}.

Also.:

Sometimes it made me doubt / question my act of sharing, especially when I was tired.

I know that, just like in our e-commerce industry, people tend not to express their opinions when there are positive evaluations, but to offer them when there are negative ones.

suggestion: “…people tend to keep their positive opinions to themselves, but are more vocal about their negative opinions.”

But still, emotions always don'tnever follow reasons.

We say “never” instead of “always don’t,” but I wonder if maybe “don’t always” might be closer to what you want to say: emotions don’t always follow reason.

I use the Jianying APPapp to add music to my videos because it offers lots of free music for which it has already paid copyright feesthe copyright fees have been paid.

Instead of I use, it should be I used: past tense

When YouTube found out about the music problem, it would offered some replaceable options.

Saying it would offer makes it seem like it didn't happen, it offered would be better

There wasI had another music problem whenile I was uploading a new video to YouTube.

I use Jianying APP to add music to my videos because it offers lots of free music for which it hasthey've already paid copyright fees.

But sometimes, those don't cover the copyright on YouTube.

It was really annoying because everyach time, I had chose then music that matched my feelings in the video.

"Every time" implies that there will be another clause, similarly to what you've done below. I've used a comma to make this sentence read a little better, and I've re-worded it to sound just a little more natural.

Whenever YouTube found thea music problem, it would offer some replaceablement options.

"Replaceable options" implies that the options themselves can be replaced, which doesn't really make sense.

It' was nice and thoughtful, but it' was difficult to find an alternative that matchesd my feelings.

I'm pretty sure this should be in past tense.

Also.,

I know that, just like in our e-commerce industry, people tend not to express their opinions when therey are positive evaluations, but to offer them when therey are negative ones.

Alternatively: "...people tend not to express their opinions when there are positive things to say, but offer them when there are negative things."

"Evaluation" is a very fancy word. To me, an "evaluation" is purely for business, or maybe education. Wikipedia describes it as "a systematic determination and assessment of a subject's merit, worth and significance". Basically: a very serious and professional review.

But still, emotions don't always don't follow reasons.

There wasI had another music problem when uploading a new video to YouTube.

"There was" is perfectly fine here, but it's often good to be less passive when opening a story. Saying "I had" puts you as a character in the story from the beginning.

I use the Jianying APPapp to add music to my videos because it offers lots of free music for which it hassince they've already paid the copyright fees.

Don't forget to add the "the" before a noun (like "app"). Also, there's nothing grammatically wrong with the end of the sentence, it just sounds a little formal and technical. I've added a more casual way to express the same meaning if that's of interest.

When YouTube found the music problemwasn't copyright free, it would offer some replaceable options.

It's often better to be specific.

IAlthough it's nice and thoughtful, but it's difficult to find an alternative that matches my feelings.

Just an alternate way to write this sentence.

Then the musical problem was resolved, even though my videos on YouTube would just havebe limited to those few music choices.

Another way to write this sentence. What you had makes sense, but this expresses the limitation more clearly.

But still, emotions doesn't always don't follow reasons.

I think this is a more natural way to word the expression.