This is a present known issue with Microsoft CRM on Google Chrome browser with version 73.
Below is some information from the O365 health page
O365 Service Health Overview status page
Title: Custom entities not rending in Google Chrome version 73
User Impact: Users may not be able to view entity records when using Google Chrome version 73.0.3683.86.
More Info: This is impacting only custom entities with a custom handler.
Impacted users may see a "Loading business logic" screen when attempting to view entity records. This affects creating a new record, opening an existing record, and opening a record from a sub-grid. This issue is not seen in lower versions of Google Chrome and is not seen in other web browsers.
Current Status: We have identified that, when accessing CRM entity records with the latest version of Chrome (73.0.3683.86), the records will not open. We have developed and are deploying a code fix for this issue. We will incorporate this fix into scheduled service updates during your region's upcoming maintenance window. We will continue to monitor service health throughout this process to and provide an update by the time listed below, or as events warrant.
User Experience: Users may not be able to view entity records when using Google Chrome version 73.0.3683.86.
For the time being below are the workarounds suggested.
Normally resolved by simply refreshing current record or view (F5), if unsuccessful, here are the other options. If option 1 or 2 is unsuccessful, please put in a support ticket and the support team can assist with item 3.
1. Use any other browser
2. Downgrade to Chrome v72
3. Add an "onload" handler to the forms. The "onload" handler doesn't have to do anything; it just needs to exists and that will allow the form to load.