Hello mcagymnastics! 

Thank you for connecting with the QuickBooks Community! Let's go ahead and re-enable automatic numbering, since the Custom transaction number feature may be disabled. Here's how:

1. Click the Gear icon (⚙) in the top right corner.
2. Select Account and Settings.
3. Click the Sales tab from the left-hand menu.
4. Go to the Sales form content section and click the pencil icon to edit.
5. Check the box for Custom transaction numbers.
6. Click Save and then Done.
7. Open a new journal entry and manually enter the correct starting number in the Journal no. field.
8. Click Save and close. 

From there, please verify for me that the following journal entry numbers are sequential from that point forward. If this is not the case, let me know by replying below.  

I will be here awaiting your update. Take care. 

Custom transaction button is on. Do you want me to turn off the custom transaction button? Per the attached screen shot when I followed the steps you provided it is not disabled.

It used to work fine and about a month or so it stopped creating automatic numbers. 

"Lets go ahead and re-enable automatic numbering, since the Custom Transaction number feature maybe disabled. Here's how:"

Thanks for following up after trying those steps, mcagymnastics.

The Custom Transaction Numbers option will need to be on for automatic sequential numbering on the journal entries. Since you saw that it was already on and the entries weren't automatically numbering, I recommend clearing the cache to rule out any browser related issues. The cache is in place to collect frequently used data to make loading web pages quicker and easier. If it gets too full it can potentially cause certain viewing and performance errors within the system. Clearing the cache will remove what's causing the communication to be broken with the numbering function. Here's how to get this done in Chrome for example:

1. At the top right, select the More ⋮ icon.
2. Select Settings.
3. Select Privacy and security.
4. Select Cookies and other site data.
5. Select See all cookies and site data.
6. Type “intuit” in the search bar to find Intuit cookies.
7. Select Remove all shown or the trash can icon.
8. Restart Google Chrome for the changes to take effect.

The following article provides similar steps depending on which browser you're using: Clear cache and cookies to fix issues when using QuickBooks Online

Please give this a try and let me know how things look afterward. I'll be here if you have any other questions.